Porcine reproductive and respiratory syndrome virus and methods of use

ABSTRACT

The present invention provides isolated European-like porcine reproductive and respiratory syndrome viruses, polynucleotides, and polypeptides. The present invention also provides methods for making antibodies to the viruses and polypeptides, methods for detecting porcine reproductive and respiratory syndrome viruses, immunogenic compositions, and methods for treating a porcine subject at risk of infection by, or displaying symptoms of, a porcine reproductive and respiratory syndrome virus infection.

CONTINUING APPLICATION DATA

[0001] This application claims the benefit of the following U.S. Provisional Applications: Serial No. 60/181,041. filed Feb. 8, 2000; Serial No. 60/193,220, filed Mar. 30, 2000; Serial No. 60/206,624, filed May 24. 2000; Serial No. 60/215,373, filed Jun. 29, 2000; and Serial No. 60/______, filed Jan. 5, 2001, docket number 110.0125 0164, entitled PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS AND METHOD OF DETECTION; each of which is incorporated by reference herein.

BACKGROUND

[0002] Porcine reproductive and respiratory syndrome virus (PRRSV) is a member of the family Arteriviridae in the order Nidovirales (Cavanagh et al., Virol., 176, 306-307 (1990)) that causes reproductive failure in breeding swine and respiratory problems in young pigs (see Rossow, Vet. Pathol., 35, 1-20 (1998)). The syndrome was first recognized as a “mystery swine disease” in the United States in 1987 and was discovered in Europe in 1990. A strain of PRRSV that is prevalent in Europe has been isolated and is referred to as the Lelystad virus (Wensvoort et al., Vet. Q., 13, 121-130(1991)). A North American PRRSV, referred to as VR-2332, has been isolated (Collins et al., J. Vet. Diagn. Investig., 4, 117-126 (1992)). The disease has also been referred to as Wabash syndrome, mystery pig disease, porcine reproductive and respiratory syndrome, swine plague, porcine epidemic abortion and respiratory syndrome, blue abortion disease, blue ear disease, abortus blau, and seuchenhafter spatabort der schweine. The disease is characterized by reproductive failure in pregnant sows and respiratory problems in pigs of all ages. The disease has a significant negative impact on the swine industry.

[0003] PRRSV is an enveloped positive single-stranded RNA virus. The 5′-capped and 3′-polyadenylated RNA of the virus is polycistronic, containing (5′ to 3′) two large replicase open reading frames (ORFs), 1a and 1b, and several smaller ORFs. In the infected cell, arteriviruses produce a nested set of six to eight major coterminal subgenomic mRNAs (sgmRNAs) each thought to express only the relative 5′-terminal ORF. These sgmRNAs have a leader sequence derived from the 5′ end of the genome that is joined at specific leader-body junction sites located downstream by an unclear discontinuous transcription mechanism (Lai, Adv. Exp. Med. Biol., 380, 463-471 (1995)). The sgmRNAs of PRRSV encode four glycoproteins (GP2 to 5, encoded by sgmRNAs 2 to 5), an unglycosylated membrane protein (M, encoded by sgmRNA 6), and a nucleocapsid protein (N, encoded by sgmRNA 7). The European prototype strain of PRRSV, Lelystad, contains all six of these proteins in the virus particle, but only the proteins encoded by ORFs 5 to 7 have conclusively been demonstrated to be in the virion of North American isolates.

[0004] Nucleotide and amino acid sequence comparisons of the 3′-terminal ORFs 2 to 7 have shown that there are significant differences between PRRSV strains native to Europe and those found in North America (Kapur et al., J. Gen. Virol., 77, 1271-1276 (1996), Murtaugh et al., Arch. Virol, 40, 1451-1460 (1995)). Substantial variation also occurs among North American PRRSV isolates. Genotypic comparison between strains VR-2332 and Lelystad has revealed that ORF 1a of VR-2332 is vastly different from that of Lelystad in both length and sequence, while ORF 1b is relatively conserved between the two strains of PRRSV. The 5′ leader sequence of VR-2332 was 31 bases shorter than that of Lelystad and differed considerably in nucleotide sequence. Regional amino acid sequence comparisons also revealed that although the recognized functional domains of the ORF 1a proteins were present in both strains, the proteins were not well conserved between these domains. Thus, although these two PRRSV strains cause similar diseases, they are different in the genes encoding structural proteins.

[0005] PRRSV continues to cause significant economic losses throughout the world. Vaccines are available, but they are based on one PRRSV strain, and there is evidence that PRRSV strains vary at the antigenic and genetic levels. In addition, since the virus was identified in Europe and in the United States, new disease phenotypes have continued to emerge.

SUMMARY OF THE INVENTION

[0006] The present invention represents the identification of a novel porcine reproductive and respiratory syndrome virus (PRRSV). It is known to the art that there is a great deal of nucleotide sequence variation between European PRRSV associated with European outbreaks of mystery swine disease (MSD) and North American PRRSV associated with North American outbreaks of MSD. As used herein the terms “European PRRSV” and “European strain” are used interchangeably and refer to strains of PRRSV that are prevalent in Europe. An example of a “European PRRSV” that is known to the art is the prototypic European strain, Lelystad, which is available from the Collection Nationale De Cultures De Microorganisms, Institut Pasteur, France, as deposit number 1-1102 (see Wensvoort et al., U.S. Pat. No. 5,620,691). The nucleotide sequence of the Lelystad strain is available at Genbank Accession Number NC_(—)002533. As used herein the terms “North American PRRSV” and “North American strain” are used interchangeably and refer to strains of the PRRSV that are prevalent in North America. An example of a “North American PRRSV” that is known to the art is the prototypic North American strain, VR-2332, which is available from the ATCC as deposit number VR-2332. The nucleotide sequence of the VR-2332 strain is available at Genbank Accession Number U87392.

[0007] The PRRSV described herein has not been described before, and was associated with a North American outbreak of MSD, but unexpectedly and surprisingly has a nucleotide sequence that has more similarity to European PRRSV strains, than to North American PRRSV strains. As used herein the phrase “European-like PRRSV” and “European-like strain” are used interchangeably and refer to PRRSV of the present invention. The characteristics of European-like PRRSV are described herein.

[0008] The present invention provides an isolated virus deposited under ATCC Accession Number PTA-2194, and an isolated cell comprising the virus. Also provided by the invention is an isolated virus that includes an RNA polynucleotide that includes the RNA nucleotide sequence corresponding to SEQ ID NO: 1. The invention provides an isolated polynucleotide that includes the sequence SEQ ID NO: 1. The isolated polynucleotide can have at least about 96% identity with a polynucleotide having the sequence shown in SEQ ID NO: 1 using a GAP algorithm with default parameters, wherein the polynucleotide replicates in a cell.

[0009] Also provided is a vector that includes a polynucleotide that includes the sequence shown in SEQ ID NO: 1, and a polypeptide that includes an amino acid sequence selected from the group consisting of SEQ ID NO:2-10. The invention provides polypeptides that have an amino acid sequence having at least about 95% identity to SEQ ID NO:2, at least about 99% identity to SEQ ID NO:3, at least about 98% identity to SEQ ID NO:4, at least about 94% identity to SEQ ID NO:5, at least about 95% identity to SEQ ID NO:6, at least about 91% identity to SEQ ID NO:7, at least about 99% identity to SEQ ID NO:9, or at least about 99.5% identity to SEQ ID NO: 10.

[0010] The invention provides an antibody that specifically binds a European-like porcine reproductive and respiratory syndrome virus (PRRSV), and a method of making an antibody. The method includes administering to an animal a virus particle that includes an RNA polynucleotide that includes the RNA nucleotide sequence corresponding to SEQ ID NO: 1, or a polypeptide that includes an amino acid sequence selected from the group consisting of SEQ ID NO:2-10, or a polynucleotide encoding the polypeptide. The particle, polypeptide, or polynucleotide is administered in an amount effective to cause the production of an antibody specific for the virus particle. The antibody can be a polyclonal antibody or a monoclonal antibody, and the method can further include isolating the antibody. Also provided is the antibody produced by the method.

[0011] Methods for detecting a PRRSV are also provided. A method includes contacting a virus particle, for instance from a biological sample, with an antibody of the present invention under conditions to form a complex with a virus particle, and detecting the complex, wherein the presence of the complex indicates the presence of a PRRSV. The method can also be used to detect PRRSV in a porcine subject. Also provided is a kit for use in detecting PRRSV in a porcine subject. The kit includes the antibody of the invention and instructions for using the antibody.

[0012] Methods for detecting the presence of a European-like PRRSV are also provided. The methods include contacting a viral polynucleotide with a first primer and a second primer under conditions suitable to form a detectable amplification product. The first primer includes a nucleotide sequence that is complementary to nucleotides 2268 and 2269 of SEQ ID NO:1 or the complement thereof. The method further includes detecting an amplification product, wherein the detection indicates that the viral polynucleotide is a European-like PRRSV. Examples of first primers that can be used include 5′ATCGGGAATGCTCAGTCCCCTT (SEQ ID NO:12), and 5′-AAGGGGACTGAGCATTCCCG (SEQ ID NO:14). The method can also be used for detecting the presence of a European-like PRRSV in a porcine subject, and includes contacting a biological sample of a porcine subject with the first primer and the second primer. The biological sample preferably includes lung tissue.

[0013] Also provided by the invention is a kit for use in detecting PRRSV in a porcine subject. The kit includes the first primers and second primers of the invention suitable for use in amplification of a portion of a PRRSV and instructions for using the primer pair. Another kit provided by the invention is for use in detecting antibody to PRRSV in a porcine subject. The kit includes the virus of the invention and instructions for using the virus.

[0014] Further provided by the invention is an immunogenic composition. The composition includes an attenuated or inactivated PRRSV that includes a polynucleotide having at least about 96% identity with a polynucleotide having the sequence shown in SEQ ID NO: 1 using a GAP algorithm with default parameters. The immunogenic composition may include a polypeptide selected from the group consisting of SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, an immunogenic analog thereof, an immunogenic fragment thereof, or a combination thereof.

[0015] Methods of treating a porcine subject at risk of infection with a PRRSV or displaying symptoms of a PRRSV infection are also provided. The methods include administering to the animal an immunogenic composition that includes an attenuated or inactivated PRRSV that includes a polynucleotide having at least about 96% identity with comprising an RNA polynucleotide comprising the RNA nucleotide sequence corresponding to SEQ ID NO: 1 using a GAP algorithm with default parameters. The immunogenic composition is administered in an amount effective to cause an immune response to the PRRSV. The immunogenic composition can include a polypeptide selected from the group consisting of SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, an immunogenic analog thereof, an immunogenic fragment thereof, or a combination thereof. Alternatively, the porcine subject can be administered a neutralizing antibody in an amount effective to treat the porcine subject.

[0016] Unless otherwise specified, “a,” “an,” “the,” and “at least one” are used interchangeably and mean one or more than one.

BRIEF DESCRIPTION OF THE FIGURES

[0017]FIG. 1. DNA nucleotide sequence of a portion of the positive strand of the genome of the European-like strain (SEQ ID NO: 1). The RNA sequence that corresponds to SEQ ID NO: 1 and is present in a viral particle has uracil (U) nucleotides instead of the thymidine (T) residues. Rows 1, 2, and 3 under the nucleotide sequence represent the three different reading frames. The predicted amino acid sequences encoded by the European-like strain are depicted for some predicted open reading frames, including: SEQ ID NO:2 (ORF1 a), SEQ ID NO:3 (ORF1b), SEQ ID NO:4 (ORF2), SEQ ID NO:5 (ORF3), SEQ ID NO:6 (OFR4), SEQ ID NO:7 (ORF5), SEQ ID NO:8, SEQ ID NO:9 (ORF6), and SEQ ID NO: 10 (ORF7).

[0018]FIG. 2. DNA nucleotide sequence of a portion of the positive strand of the genome of the European-like strain (nucleotides 1,830 to 2,618 of SEQ ID NO: 1) compared to a portion of the DNA nucleotide sequence of the prototypic European strain Lelystad (SEQ ID NO 11, which corresponds to nucleotides 1,981 to 2,820 of Genbank Accession Number NC_(—)002533). In SEQ ID NO: 11, the upper case nucleotides signify aligned non-identical nucleotides; lower case nucleotides signify unaligned nucleotides; dashes signify aligned identical nucleotides; and dots signify a gap.

DETAILED DESCRIPTION OF THE INVENTION

[0019] Polynucleotides

[0020] The present invention is based on the the identification of a novel porcine reproductive and respiratory syndrome virus (PRRSV), an enveloped positive single-stranded RNA virus. Accordingly, the present invention provides isolated polynucleotides. Preferably, an isolated polynucleotide can replicate in a cell. Preferably, an isolated polynucleotide of the present invention is no greater than about 15.3 kilobases. Whether an isolated polynucleotide can replicate in a cell can be determined by inserting the polynucleotidc into an expression vector, producing an infectious RNA, introducing the infectious RNA to a cells, and evaluating if the infectious RNA causes the cell to produce virus particles. These methods are described in greater detail herein. A preferred example of a polynucleotide of the present invention is SEQ ID NO: 1 (FIG. 1). This polypeptide is a portion of a polynucleotide obtained from a European-like PRRSV. Preferably, the European-like PRRSV is one having the strain designation MND99-35186, and deposited with the American Type Culture Collection, 10801 University Blvd., Manassas, Va., 20110-2209, USA, on Jul. 7, 2000 (granted ATCC Accession Number PTA-2194).

[0021] The deposit was made under the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure. It is expected that the complete nucleotide sequence of the PRRSV disclosed in SEQ ID NO: 1 will include additional nucleotides at the 5′ end of the polynucleotide. Specifically, it is expected that about 100 to about 200, preferably about 150, additional nucleotides can be present at the 5′ end of SEQ ID NO: 1 when the nucleotide sequence of the entire PRRSV represented by SEQ ID NO: 1 is determined. It should be noted that while SEQ ID NO: 1 is a DNA sequence, the present invention contemplates the corresponding RNA sequence, and RNA and DNA complements thereof, as well.

[0022] As used herein, an “isolated” substance is one that has been removed from its natural environment, produced using recombinant techniques, or chemically or enzymatically synthesized. For instance, a polypeptide, polynucleotide, or virus particle of this invention can be isolated. Preferably, a polypeptide, polynucleotide, or virus particle of this invention is purified, i.e., essentially free from any other type of polypeptide, polynucleotide, or virus particle and associated cellular products or other impurities. As used herein, the term “polynucleotide” refers to a polymeric form of nucleotides of any length, either ribonucleotides or deoxynucleotides, and includes both double- and single-stranded DNA and RNA. Unless otherwise noted, a polynucleotide includes the complement thereof. The nucleotide sequence of the complement of a polynucleotide can be easily determined by a person of skill in the art. A polynucleotide may include nucleotide sequences having different functions, including for instance coding sequences, and non-coding sequences such as regulatory sequences and/or non-translated regions. A polynucleotide can be obtained directly from a natural source, or can be prepared with the aid of recombinant, enzymatic, or chemical techniques. A polynucleotide can be linear or circular in topology. A polynucleotide can be, for example, a portion of a vector, such as an expression or cloning vector, or a fragment.

[0023] “Polypeptide” as used herein refers to a polymer of amino acids and does not refer to a specific length of a polymer of amino acids. Thus, for example, the terms peptide, oligopeptide, protein, and enzyme are included within the definition of polypeptide. This term also includes post-expression modifications of the polypeptide, for example, glycosylations, acetylations, phosphorylations and the like.

[0024] The terms “coding region” and “coding sequence” are used interchangeably and refer to a polynucleotide region that encodes a polypeptide and, when placed under the control of appropriate regulatory sequences, expresses the encoded polypeptide. The boundaries of a coding region are generally determined by a translation start codon at its 5′ end and a translation stop codon at its 3′ end. A regulatory sequence is a polynucleotide sequence that regulates expression of a coding region to which it is operably linked. Nonlimiting examples of regulatory sequences include promoters, transcription initiation sites, translation start sites, translation stop sites, and terminators. “Operably linked” refers to a juxtaposition wherein the components so described are in a relationship permitting them to function in their intended manner. A regulatory sequence is “operably linked” to a coding region when it is joined in such a way that expression of the coding region is achieved under conditions compatible with the regulatory sequence.

[0025] “Complement” and “complementary” refer to the ability of two single stranded polynucleotides to base pair, i.e., hybridize, with each other, where an adenine of one polynucleotide will base pair to a thymine of a second polynucleotide and a cytosine of one polynucleotide will base pair to a guanine of a second polynucleotide. Two polynucleotides are complementary to each other when a nucleotide sequence in one polynucleotide can base pair with a nucleotide sequence in a second polynucleotide. For instance, 5′-ATGC and 5′-GCAT are complementary. The terms complement and complementary also encompass two polynucleotides where one polynucleotide contains at least one nucleotide that will not base pair to at least one nucleotide present on a second polynucleotide under the hybridization conditions described below. For instance the third nucleotide of each of the two polynucleotides 5′-ATTGC and 5′-GCTAT will not base pair, but these two polynucleotides are complementary as defined herein.

[0026] The present invention also provides isolated polynucleotides that correspond to the coding regions present in SEQ ID NO:1. These coding regions are shown in Table 1. TABLE 1 Coding regions of SEQ ID NO: 1 Nucleotides of SEQ ID NO: 1 corresponding Polypeptide encoded by the SEQ ID NO of the to the coding region. coding region. polypeptide.    71 to 7,210 ORF1a SEQ ID NO: 2  7,207 to 11,583 ORF1b SEQ ID NO: 3 11,594 to 12,343 ORF2 SEQ ID NO: 4 12,202 to 12,994 ORF3 SEQ ID NO: 5 12,744 to 13,295 ORF4 SEQ ID NO: 6 13,292 to 13,897 ORF5 SEQ ID NO: 7 13,449 to 13,775 not applicable SEQ ID NO: 8 13,885 to 14,406 ORF6 SEQ ID NO: 9 14,396 to 14,782 ORF7 SEQ ID NO: 10

[0027] The present invention also includes polynucleotides having structural similarity to SEQ ID NO:1 or to a coding region present in SEQ ID NO:1. The similarity is referred to as “percent identity” and is determined by aligning the residues of the two polynucleotides (i.e., the nucleotide sequence of a candidate polynucleotide and the nucleotide sequence of SEQ ID NO:1 or a coding region of SEQ ID NO: 1) to optimize the number of identical nucleotides along the lengths of their sequences; gaps in either or both sequences are permitted in making the alignment in order to optimize the number of shared nucleotides, although the nucleotides in each sequence must nonetheless remain in their proper order. A candidate polynucleotide is the polynucleotide that has the nucleotide sequence being compared to SEQ ID NO:1 or to a coding region present in SEQ ID NO: 1 (e.g., nucleotides 71 to 7,210 of SEQ ID NO:1). A candidate polynucleotide can be isolated from an animal, preferably a pig infected with PRRSV, or can be produced using recombinant techniques, or chemically or enzymatically synthesized. Preferably, two nucleotide sequences are compared using the GAP program of the GCG Wisconsin Package (Genetics Computer Group, Madison, Wis.) version 10.0 (update January 1999). The GAP program uses the algorithm of Needleman and Wunsch (J. Mol. Biol., 48, 443-453 (1970)) to find the alignment of two complete sequences that maximizes the number of matches and minimizes the number of gaps. Preferably, the default values for all GAP search parameters are used, including scoring matrix=NewsgapDNA.cmp, gap weight=50, length weight=3, average match=10, average mismatch=0. In the comparison of two nucleotide sequences using the GAP search algorithm, structural similarity is referred to as “percent identity.” Preferably, a polynucleotide includes a nucleotide sequence having a structural similarity with a coding region of SEQ ID NO:1 of at least about 96%, more preferably at least about 98%, most preferably at least about 99% identity.

[0028] Another isolated polynucleotide provided by the invention is an RNA polynucleotide to which an oligonucleotide having the sequence AGAGCGGGAACAGAATCCTTCCCACCTTTAGCGGTACGCTTG (SEQ ID NO:18) hybridizes. Preferably, the RNA polynucleotide replicates in cells to form virus particles. Such an RNA is referred to as an infectious RNA. The production and testing of infectious RNAs are described in greater detail below. Preferably, hybridization conditions include denaturing about 1 μg total RNA with glyoxyl and electrophoresing through a 2% agarose gel, transferring to a nylon membrane (MagnaGraph, MSI, Westboro, Mass.), and crosslinking to the membrane by ultraviolet light. Preferably, the oligonucleotide is 3-end radiolabeled, for instance with [α³²P]dATP (Amersham Life Science, Arlington Heights, Ill.) and terminal deoxynucleotide transferase (TdT) (Promega Corporation, Madison, Wis.). Preferably, hybridization conditions include incubation of the membrane containing the crosslinked RNA with the labeled oligonucleotide in a hybridization solution, for instance QuikHyb (Stratagene, La Jolla, Calif.) at 68° C. for 16 hours. The membrane is then washed 3 times in a solution containing 0.9 M sodium chloride/0.09 M sodium citrate/pH 7.0 (6×SSC) and 0.5% sodium dodecyl sulfate (SDS) at 78° C., and then exposed to autoradiography film (NEN Life Science Products, Boston, Mass.) or a phosphoimaging screen (Molecular Dynamics, Inc., Sunnyvale, Calif.). It is expected that under these conditions, the oligonucleotide will not hybridize to the European PRRSV Lelystad or to the North American PRRSV VR-2332.

[0029] Preferably, a polynucleotide of the present invention includes a deletion when compared to the nucleotide sequence of European strain Lelystad, which is available at Genbank Accession Number NC_(—)002533. When the nucleotide sequence of SEQ ID NO:1 and Genbank Accession Number NC_(—)002533 are compared, nucleotides 2,419 to 2,470 of Genbank Accession Number NC_(—)002533 are not present in SEQ ID NO: 1. Nucleotides 2268 and 2269 of SEQ ID NO: 1 are immediately 5′ (upstream) and 3′ (downstream) of this deletion. Thus, those polynucleotides of the present invention that include nucleotides 2268 and 2269 of SEQ ID NO:1 include this deletion. The presence of this deletion is useful in distinguishing between a polynucleotide of the present invention and some PRRSV clinical isolates (described in greater detail herein).

[0030] The isolated polynucleotides of the present invention can be obtained from a virus particle. As used herein, the terms “virus particle” and “viral particle” are used interchangeably and refer to a PRRSV particle. A virus particle includes an RNA polynucleotide that will reproduce in a cell, for instance a cell in a pig and/or a cultured primary (i.e., freshly isolated) porcine alveolar macrophage, under the appropriate conditions. A virus particle also includes an envelope that surrounds the polynucleotide. A virus particle is typically obtained from a pig presenting symptoms of mystery swine disease (MSD), including abortion, anorexia, fever, lethargy, pneumonia, red/blue discoloration of ears, labored breathing (dyspnea), and increased respiratory rate (tachypnea). While not intending to be limiting, a virus particle can be obtained from such a pig by the removal of tissue, preferably lung tissue, followed by microscopic examination of the tissue for thickened alveolar septae caused by the presence of macrophages, degenerating cells, and debris in alveolar spaces. These characteristics indicate the presence of an infection by a PRRSV. The lung or other porcine tissue is then homogenized with a pharmaceutically acceptable aqueous solution (such as physiological saline, Ringers solution, Hank's Balanced Salt Solution, Minimum Essential Medium, and the like) such that the tissue includes about 10 percent weight/volume amount of the homogenate. The virus can be isolated by low speed centrifugation as described in Example 1 to form a homogenate. Alternatively, the virus can be isolated by passing the homogenate through filters with pore diameters in the 0.05 to 10 micron range, preferably through a series of 0.45, 0.2 and 0.1 micron filters, to produce a homogenate containing the PRRSV. As a result, the homogenate contains viral particles having a size no greater than about 1.0 micron, preferably no greater than about 0.2 to 0.1 micron. Other tissues, including fetal tissue, may also be used to recover virus. Typically, such a virus particle is then grown in vivo (i.e., within the body of a subject) or in cell culture (i.e., in vitro) to produce more virus particles. This process of infecting an animal or a cell in culture, allowing the virus to reproduce, and then harvesting the newly produced virus is referred to herein as passaging the virus. Optionally, the virus is purified.

[0031] The homogenate described above can be passaged in cell culture by inoculation into a series of cultured cells. Cultured cells can be mammalian organ cells such as kidney, liver, heart and brain, lung, spleen, testicle, turbinate, white and red blood cells and lymph node cells, as well as insect and avian embryo preparations. Preferably, the cell is a primary porcine alveolar macrophage. Preferably, primary porcine alveolar macrophages are isolated from at least two pigs, and the primary porcine alveolar macrophages from each pig are not combined. It has been observed that there is some variability in the ability of the virus of the present invention to replicate in primary porcine alveolar macrophage, and the use of primary porcine alveolar macrophages from more than one pig significantly increases the ability to passage the virus in the macrophages. Culture media suitable for these cell preparations include those supporting mammalian cell growth such as serum (for instance, fetal calf serum or swine serum) and agar, blood infusion agar, brain-heart infusion glucose broth and agar and the like. After inoculating cultured cells with homogenate and growing the culture, individual clumps of cultured cells can be harvested and reintroduced into sterile culture medium with cells. Alternatively and preferably, supernatants from cultured cells are subjected to low speed centrifugation and used to inoculate sterile culture medium containing cells.

[0032] Whether an isolated, preferably purified, virus particle obtained in this way is able to cause MSD can be determined by inoculation of 3 to 4 week old pigs as described in Example 1, or by the methods of Terpstra et al., (Vet. Q., 13, 131-136 (1991)), and Collins et al., (U.S. Pat. No. 5,846,805). These methods experimentally test if the viral particle reproduces late term abortion and reproductive failure in pregnant sows or clinical signs and microscopic lesions in gnotobiotic piglets similar to field outbreaks. Pigs experimentally inoculated in this manner can also be used for in vivo passage of the virus by collecting tissue and processing for the isolation of virus as described in Example 1.

[0033] After isolation, preferably purification, of the virus particle, the polynucleotide in the particle can be isolated by, for instance, treating the particle to remove the envelope. Methods for removing the envelope are known in the art and include, for instance, solubilizing with phenol:chloroform or guanidunium. Optionally, the polynucleotide is purified using methods known to the art, including, for instance, precipitating the polynucleotide.

[0034] The polynucleotides of the present invention can be present in a vector. A vector is a replicating polynucleotide, such as a plasmid, phage, cosmid, or artificial chromosome to which another polynucleotide (e.g., a polynucleotide of the present invention) may be attached so as to bring about the replication of the attached polynucleotide. When a polynucleotide of the present invention is in a vector the polynucleotide is DNA. When present in a vector, a polynucleotide of the invention can be referred to as a “recombinant polynucleotide.”Construction of vectors containing a polynucleotide of the invention employs standard ligation techniques known in the art. See, e.g., Sambrook et al, Molecular Cloning: A Laboratory Manual., Cold Spring Harbor Laboratory Press (1989) or Ausubel, R. M., ed. Current Protocols in Molecular Biology (1994).

[0035] A vector can provide for further cloning (amplification of the polynucleotide), i.e., a cloning vector, or for expression of the polypeptide encoded by a coding region present in the polynucleotide, i.e., an expression vector. Selection of a vector depends upon a variety of desired characteristics in the resulting construct, such as a selection marker, vector replication rate, and the like. Suitable host cells for cloning or expressing the vectors herein are prokaryote or eukaryotic cells, and suitable vectors for cloning and/or expression in prokaryote and/or eukaryote cells are known to the art. Typically, when the vector is used to clone a polynucleotide, the host cell is a prokaryote. Suitable prokaryotes include eubacteria, such as gram-negative or gram-positive organisms. Preferably, E. coli is used. Host cells suitable for expression of the polypeptides of the invention are described in greater detail below.

[0036] The polynucleotide used to transform the host cell optionally includes one or more marker sequences, which typically encode a molecule that inactivates or otherwise detects or is detected by a compound in the growth medium. For example, the inclusion of a marker sequence can render the transformed cell resistant to an antibiotic, or it can confer compound-specific metabolism on the transformed cell. Examples of a marker sequence are sequences that confer resistance to kanamycin, ampicillin, chloramphenicol, tetracycline, neomycin, and formulations of phleomycin D1 including, for example, the formulation available under the trade-name ZEOCIN (Invitrogen).

[0037] An expression vector optionally includes regulatory sequences operably linked to the coding sequence. The invention is not limited by the use of any particular promoter, and a wide variety are known. Promoters act as regulatory signals that bind RNA polymerase in a cell to initiate transcription of a downstream (3′ direction) coding sequence. The promoter used in the invention can be a constitutive or an inducible promoter. It can be, but need not be, heterologous with respect to the host cell. Examples of promoters for use in vectors present in prokaryotic cells include lac, lacUV5, tac, trc, T7, SP6 and ara.

[0038] Promoter sequences are known for eukaryotes. Most eukaryotic coding sequences have an AT-rich region located approximately 25 to 30 bases upstream from the site where transcription is initiated. Another sequence found 70 to 80 bases upstream from the start of transcription of many genes is the CXCAAT region where X may be any nucleotide. At the 3′ end of most eukaryotic genes is an AATAAA sequence that may be a signal for addition of the poly A tail to the 3′ end of the coding sequence. All these sequences are suitably inserted into eukaryotic expression vectors.

[0039] Transcription of a coding sequence encoding a polypeptide of the present invention in mammalian host cells can be controlled, for example, by promoters obtained from the genomes of viruses such as polyoma virus, fowlpox virus, adenovirus (such as Adenovirus 2), bovine papilloma virus, avian sarcoma virus, cytomegalovirus, a retrovirus, and Hepatitis-B virus.

[0040] Transcription of a coding sequence encoding a polypeptide of the present invention by eukaryotes can be increased by inserting an enhancer sequence into the vector. Enhancers are cis-acting elements of DNA, usually having about 10 to 300 bp, that act on a promoter to increase its transcription. Enhancers are relatively orientation- and position-independent, having been found 5′ and 3′ to coding sequences, within an intron as well as within the coding sequence itself. Many enhancer sequences are now known from mammalian genes (globin, elastase, albumin, alpha-fetoprotein, and insulin). Enhancers from eukaryotic cell viruses are also known and include the SV40 enhancer on the late side of the replication origin, the cytomegalovirus early promoter enhancer, the polyoma enhancer on the late side of the replication origin, and adenovirus enhancers. The enhancer may be spliced into the vector at a position 5′ or 3′ to the coding sequence encoding a polypeptide of the present invention, but is preferably located at a site 5′ of the promoter.

[0041] An expression vector can optionally include a ribosome binding site (a Shine Dalgarno site for prokaryotic systems or a Kozak site for eukaryotic systems) and a start site (e.g., the codon ATG) to initiate translation of the transcribed message to produce the enzyme. It can also include a termination sequence to end translation. A termination sequence is typically a codon for which there exists no corresponding aminoacetyl-tRNA, thus ending polypeptide synthesis. The polynucleotide used to transform the host cell can optionally further include a transcription termination sequence. The rrnB terminators, which is a stretch of DNA that contains two terminators, T1 and T2, is an often used terminator that is incorporated into bacterial expression systems. Transcription termination sequences in vectors for eukaryotic cells typically include a polyadenylation signal 3′ of the coding sequence.

[0042] Suitable host cells for expression vector that includes a polynucleotide encoding a polypeptide of the invention can be derived from multicellular organisms. Such host cells are capable of processing and glycosylation activities. Vertebrate or invertebrate culture can be used. Numerous baculoviral strains and variants and corresponding permissive insect host cells from hosts such as Spodoptera frugiperda, Aedes aegypti, Aedes albopictus, Drosophila melanogaster, Trichoplusia ni, and Bombyx mori are known to the art.

[0043] Vertebrate cells can also be used as hosts. Examples of useful mammalian host cell lines are monkey kidney CV1 line transformed by SV40 (CAS-7, ATCC CRL-1651); human embryonic kidney line (293 or 293 cells subcloned for growth in suspension culture, Graham et al., J. Gen. Virol., 36:59 (1977)); baby hamster kidney cells (BHK, ATCC CCL 10); Chinese hamster ovary cells/-DHFR (CHO); CHO-K1 (ATCC CCL-61); CHO-D; mouse sertoli cells (TM4); monkey kidney cells (CV1, ATCC CCL 70); African green monkey kidney cells (VERO-76, ATCC CRL-1587); human cervical carcinoma cells (HELA, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34); buffalo rat liver cells (BRL 3A, ATCC CRL 1442); human lung cells (WI 38, ATCC CCL 75); human liver cells (Hep G2, HB 8065); mouse mammary tumor (MMT 060562, ATCC CCL 51); TRI cells; MRC 5 cells; FS4 cells; a human hepatoma line (Hep G2), MARC-145 (Kim et al., Arch. Virol., 133, 477-483 (1993)), and MA-104 (ATCC CRL-2378).

[0044] An expression vector of the present invention can be used to determine if a polynucleotide of the present invention replicates in a cell. A polynucleotide of the invention replicates in a cell if the cell culture shows signs of cytopathic effect (CPE) as described in Example 2, and/or if virus particles can be isolated from the cells. The polynucleotide present in the expression vector can be transcribed in vitro (i.e., cell free) to produce RNA transcripts. The RNA transcripts can be introduced into cultured cells, and incubated under conditions suitable for replication of a PRRSV. RNA transcripts that replicate will use the cellular machinery (including, for instance, ribosomes, and tRNAs) to replicate. The culture can be assayed as described in Example 2 for CPE. The presence of CPE indicates the virus is able to replicate in a cell. Optionally, the virus particles produced by the cells can be isolated. This type of expression vector is often referred to in the art as an infectious cDNA clone, and the RNA produced by the expression vector is referred to as an infectious RNA. Methods for cloning the European PRRSV Lelystad and inserting it into a vector are known to the art (Meulenberg et al., J. Virol, 72, 380-387 (1998)), and it is expected that the polynucleotides of the present invention can be used in this way to produce infectious RNAs. Moreover, the method of Meulenberg et al. can be used to make viral particles. Accordingly, a person of skill in the art can provide a polynucleotide of the present invention, for instance SEQ ID NO:1, introduce the polynucleotide into an expression vector, and produce infectious RNAs that could be introduced to cells to result in the production of virus particles. The cells transfected with an infectious RNA can be, for instance, BHK-21 cells, CL-2621 cells, MA-104 cells, MARC-145 cells, or primary porcine alveolar macrophages, preferably primary porcine alveolar macrophages. Methods for efficiently transfecting cells include the use of calcium chloride, and commercially available products known under the trade names LIPOFECTIN and LIPOFECTAMINE. Methods for efficiently transfecting primary porcine alveolar macrophages are known to the art (Groot Bramel-Verheige et al., Virol., 278, 380-389 (2000)).

[0045] Polypeptides

[0046] The present invention is also directed to polypeptides, preferably isolated polypeptides, encoded by polynucleotides of the present invention. Preferably, a polypeptide of the present invention has immunogenic activity. “Immunogenic activity” refers to an amino acid sequence which elicits an immunological response in a subject. An immunological response to a polypeptide is the development in a subject of a cellular and/or antibody-mediated immune response to the polypeptide. Usually, an immunological response includes but is not limited to one or more of the following effects: the production of antibodies, B cells, helper T cells, suppressor T cells, and/or cytotoxic T cells (see, for example, de Antonio et al., Vet. Immunol. Immunopathol, 61, 265-277 (1998), and Kwang et al., Res. Vet. Sci., 67, 199-201 (1999)) directed specifically to an epitope or epitopes of the polypeptide fragment. As used herein, an antibody that can “specifically bind” or is “specific for” a virus particle and/or a polypeptide is an antibody that interacts only with an epitope of the antigen that induced the synthesis of the antibody, or interacts with a structurally related epitope. An antibody that “specifically binds” a European-like PRRSV is an antibody that does not specifically bind a European PRRSV, preferably a European PRRSV having deposit number 1-1102, or a North American PRRSV, preferably a North American PRRSV having deposit number VR-2332. As used herein, the term “complex” refers to the combination of an antibody and a virus particle and/or a polypeptide that results when an antibody specifically binds to a virus particle and/or a polypeptide.

[0047] Preferred examples of polypeptides of the invention are SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, and SEQ ID NO:10 (see Table 1). The present invention further includes polypeptides having structural similarity with the polypeptides of the present invention. The structural similarity is referred to as percent identity and is generally determined by aligning the residues of the two amino acid sequences (i.e., a candidate amino acid sequence and the amino acid sequence of one of SEQ ID NOs:2-10) to optimize the number of identical amino acids along the lengths of their sequences; gaps in either or both sequences are permitted in making the alignment in order to optimize the number of identical amino acids, although the amino acids in each sequence must nonetheless remain in their proper order. A candidate amino acid sequence is the amino acid sequence being compared to an amino acid sequence present in a preferred polypeptide of the present invention. Preferably, two amino acid sequences are compared using the GAP program of the GCG Wisconsin Package (Genetics Computer Group, Madison, Wis.) version 10.0 (update January 1999). The GAP program uses the algorithm of Needleman and Wunsch (J. Mol. Biol., 48, 443-453 (1970) to find the alignment of two complete sequences that maximizes the number of matches and minimizes the number of gaps. Preferably, the default values for all GAP search parameters are used, including scoring matrix=BLOSUM62.cmp, gap weight=8, length weight=2, average match=2.912, and average mismatch=−2.003. In the comparison of two amino acid sequences using the GAP search algorithm, structural similarity is referred to as “percent identity.” Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO:2 of at least about 95%, more preferably at least about 97%, most preferably at least about 99% identity. Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO:3 of at least about 99% identity. Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO:4 of at least about 98%, more preferably at least about 99% identity. Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO:5 of at least about 94%, more preferably at least about 96%, most preferably at least about 99% identity. Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO:6 of at least about 95%, more preferably at least about 97%, most preferably at least about 99% identity. Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO:7 of, in increasing order of preference, at least about 91%, at least about 93%, at least about 95%, at least about 97%, most preferably at least about 99% identity. Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO:9 of at least about 99% identity. Preferably, a polypeptide includes an amino acid sequence having a structural similarity with SEQ ID NO: 10 of at least about 99.5% identity.

[0048] The present invention further includes polypeptide analogs and polypeptide fragments, preferably immunogenic polypeptide analogs and immunogenic polypeptide fragments. Preferably, a polypeptide fragment is at least about 8, more preferably at least about 12, most preferably at least about 20 amino acids in length. Immunogenic analogs of polypeptides of the present invention include polypeptides having amino acid substitutions that do not eliminate the ability of the polypeptide to elicit an immunological response.

[0049] Substitutes for an amino acid may be selected from other members of the class to which the amino acid belongs. For example, nonpolar (hydrophobic) amino acids include alanine, leucine, isoleucine, valine, proline, phenylalanine, tryptophan, and tyrosine. Polar neutral amino acids include glycine, serine, threonine, cysteine, tyrosine, aspartate, and glutamate. The positively charged (basic) amino acids include arginine, lysine, and histidine. The negatively charged (acidic) amino acids include aspartic acid and glutamic acid. Examples of preferred conservative substitutions include Lys for Arg and vice versa to maintain a positive charge; Glu for Asp and vice versa to maintain a negative charge; Ser for Thr so that a free —OH is maintained; and Gln for Asn to maintain a free NH₂.

[0050] Immunogenic analogs, as that term is used herein, also include modified polypeptides. Modifications of polypeptides of the invention include chemical and/or enzymatic derivatizations at one or more constituent amino acids, including side chain modifications, backbone modifications, and N- and C-terminal modifications including acetylation, hydroxylation, methylation, amidation, and the attachment of carbohydrate or lipid moieties, cofactors, and the like. Immunogenic fragments of a polypeptide include a portion of the polypeptide containing deletions or additions of one or more contiguous or noncontiguous amino acids such that the resulting polypeptide is immunogenic.

[0051] The polypeptides of the present invention can be obtained from, for instance, a biological sample from a porcine subject infected with a European-like PRRSV that encodes the polypeptide. Preferably, the European-like PRRSV is one that includes SEQ ID NO: 1, more preferably it is the European-like PRRSV having ATCC number PTA-2194. The polypeptide can be obtained from cultured cells, preferably primary porcine alveolar macrophages, that have, for instance, been infected with a European-like PRRSV that encodes the polypeptide or contain a recombinant polynucleotide, preferably a polynucleotide of the invention, that encodes a polypeptide of the invention. Alternatively, the polypeptide can be obtained from a prokaryotic cell or a eukaryotic cell that contains an expression vector that includes a polynucleotide encoding a polypeptide of the invention. The polypeptides of the present invention can also be obtained by chemical synthesis.

[0052] Viruses

[0053] The present invention includes isolated European-like virus particles. The European-like virus particles of the present invention include a polynucleotide having structural similarity to SEQ ID NO: 1, preferably at least about 96%, more preferably at least about 98%, most preferably at least about 99% identity to SEQ ID NO: 1. A preferred example of a virus particle is one that includes SEQ ID NO: 1. More preferably, the virus particle is the virus having ATCC Accession Number PTA-2194. A virus particle of the present invention include an envelope, and can, when added to a cultured cell, can replicate to result in the production of more viral particles.

[0054] As discussed above, a virus particle of the present invention can be obtained from a pig presenting symptoms of MSD. A virus particle can be grown by passage in vivo or in cell culture. Passage in vivo includes inoculating a pig, for instance as described in example 1. Passage in cell culture includes exposing cultured cells to the virus particle and incubating the cells under conditions suitable for the virus to reproduce and produce more virus particles. Preferably, the cultured cells are not an immortalized or transformed cell line (i.e., the cells are not able to divide indefinitely). Preferably, primary porcine alveolar macrophages are used for passage in cell culture. The use of primary porcine alveolar macrophages is described in Example 2. A virus particle can also be obtained from cells transfected with an infectious RNA as described herein.

[0055] A virus of the present invention can be inactivated, i.e., rendered incapable of reproducing in vivo and/or in cell culture. Methods of inactivation are known to the art and include, for instance, treatment of a virus of the invention with a standard chemical inactivating agent such as an aldehyde reagent including formalin, acetaldehyde and the like; reactive acidic alcohols including cresol, phenol and the like; acids such as benzoic acid, benzene sulfonic acid and the like; lactones such as beta propiolactone and caprolactone; and activated lactams, carbodiimides and carbonyl diheteroaromatic compounds such as carbonyl diimidazole. Irradiation such as with ultraviolet and gamma irradiation can also be used to inactivate the virus.

[0056] Also included in the present invention are attenuated European-like PRRSV (i.e., viruses having reduced ability to cause the symptoms of MSD in pigs), and methods of making an attenuated European-like PRRSV. Methods of producing an attenuated virus are known to the art. Typically, a virus of the present invention is passaged, i.e., used to infect a cell in culture, allowed to reproduce, and then harvested. This process is repeated until the virulence of the virus in pigs is decreased. For instance, the virus can be passaged 10 times in cell culture, and then the virulence of the virus measured. If virulence has not decreased, the virus that was not injected into the animal is passaged an additional 10 times in cell culture. This process is repeated until virulence is decreased. In general, virulence is measured by inoculation of pigs with virus, and evaluating the presence of clinical symptoms and/or LD₅₀ (see, for instance, Example 1, Halbur et al., J. Vet. Diagn. Invest., 8, 11-20 (1996), and Halbur et al., Vet. Pathol., 32, 200-204 (1995), and Park et al., Am. J. Vet. Res., 57, 320-323 (1996)). Preferably, virulence is decreased so the attenuated virus does not cause the death of animals, and preferably does not cause clinical symptoms of the disease.

[0057] Typically, a cell culture useful for producing an attenuated virus of the present invention includes cells of non-porcine mammal origin. Examples of non-porcine mammal cell cultures include, for instance, the cell line MA-104 (ATCC CRL-2378), the cell line MARC-145 (Kim et al., Arch. Virol., 133, 477-483 (1993)), and the cell line CL-2621 (Baustia et al., J. Vet. Diagn. Invest., 5, 163-165 (1993)). Preferably, a mixed cell culture is used for producing an attenuated virus of the present invention. In a mixed cell culture there are at least two types of cells present. Preferably, a mixed cell culture includes an immortalized or transformed cell line and a primary cell culture. A mixed cell culture is particularly useful when a virus reproduces slowly, or not at all, in an immortalized or transformed cell line. Preferred examples of an immortalized or transformed cell line for use in a mixed cell culture include, for example, the cell line MARC-145 (Kim et al., Arch. Virol., 133, 477-483 (1993)), and the cell line MA-104 (ATCC CRL-2378). Preferably, primary cell cultures for use in a mixed cell culture are porcine in origin. A preferred example of a primary cell culture for use in a mixed cell culture is primary porcine alveolar macrophages.

[0058] Methods of Use

[0059] The virus particles, polynucleotides, polypeptides, and immunogenic analogs and immunogenic fragments thereof of the present invention can be used to produce antibodies. Laboratory methods for producing, characterizing, and optionally isolating polyclonal and monoclonal antibodies are known in the art (see, for instance, Harlow E. et al. Antibodies: A laboratory manual Cold Spring Harbor Laboratory Press, Cold Spring Harbor (1988). For instance, a virus of the present invention can be administered to an animal, preferably a mammal, in an amount effective to cause the production of antibody specific for the administered virus. Polypeptides of the present invention and immunogenic analogs and immunogenic fragments thereof can also be administered to an animal, preferably a mammal, to produce antibodies. Optionally, a virus particle or a polypeptide is mixed with an adjuvant, for instance Freund's incomplete adjuvant, to stimulate the production of antibodies upon administration. Preferably, the antibody is a monoclonal antibody.

[0060] Preferably, an antibody produced using a virus of the present invention, or a polypeptide or immunogenic analog or immunogenic fragment thereof, is a neutralizing antibody. A neutralizing antibody is one that prevents a virus of the present invention from reproducing in cell culture, preferably in primary porcine macrophages.

[0061] Optionally and preferably, antibody produced using a virus particle of the present invention, a polypeptide or polynucleotide of the present invention, or immunogenic analogs and immunogenic fragments thereof do not specifically bind to the European PRRSV deposited as I-1102 with the Collection Nationale De Cultures De Microorganisms, Institut Pasteur, France, or to the North American PRRSV deposited as VR-2332 with the ATCC. Whether an antibody of the present invention specifically binds to either or both of those viruses can be determined using methods known to the art.

[0062] The present invention provides methods for detecting a PRRSV, preferably a virus of the present invention. These methods are useful in, for instance, detecting a PRRSV in an animal, detecting a PRRSV in a cell culture, or diagnosing a disease caused by a PRRSV. Preferably, such diagnostic systems are in kit form. Kits are described in greater detail below. In some aspects of the invention, detecting a PRRSV includes detecting antibodies that specifically bind to a virus of the present invention, a polypeptide of the present invention, and/or an immunogenic analog or immunogenic fragment thereof. The method includes providing a biological sample, preferably a liquid homogenate of a tissue sample, from a porcine subject. The subject can be suspected of harboring the PRRSV, or can be a member of a herd that is being screened for the presence of the PRRSV. Antibody is added to the biological sample and incubated under conditions to form a complex with a PRRSV in the biological sample. Preferably the antibody is produced using a virus particle of the present invention, a polypeptide or polynucleotide of the present invention, or an immunogenic analog or immunogenic fragment thereof. Preferably, the antibody does not specifically bind a European PRRSV or a North American PRRSV. The complex is then detected, and the presence of the complex indicates the presence of a PRRSV in the biological sample. The detection of antibodies is known in the art and can include, for instance, immunofluorescence and peroxidase. Typical formats in which antibodies of the present invention can be used include, for instance, enzyme linked immunosorbent assay (ELISA); radioimmunoassay (RIA), immunofluorescent assay (IFA), and western immunoassay.

[0063] As used herein, a “biological sample” refers to a sample of tissue or fluid obtained from a subject, including but not limited to, for example, lung or respiratory tract. A “biological sample” also includes samples of cell culture constituents including but not limited to the cells and media resulting from the growth of cells and tissues in culture medium. The cells can be infected with PRRSV or can contain a vector that includes a polypeptide of the present invention, and preferably includes a coding region encoding a polypeptide of the present invention.

[0064] Other methods for detecting a PRRSV, preferably a European-like PRRSV, include the amplification of a polynucleotide, preferably by the polymerase chain reaction (PCR). The polynucleotide can be one that is, for instance, present in a biological sample from a porcine subject that is suspected of harboring the PRRSV, or a member of a herd that is being screened for the presence of the PRRSV. The polynucleotide can be obtained from an isolated, preferably purified, virus particle. When the polynucleotide is obtained from a virus particle, the polynucleotide is converted from an RNA polynucleotide to a DNA polynucleotide by reverse transcription (see, for instance, Example 3). In some aspects of the present invention, the methods to detect a European-like PRRSV and distinguish it from a European PRRSV and a North American PRRSV exploit the presence of a deletion present in European-like PRRSV. This deletion is described above in the section labeled “Polynucleotides.”

[0065] In one aspect of detecting a PRRSV by amplification of a polynucleotide, the invention is directed to detecting a virus of the present invention under conditions where European PRRSV and North American PRRSV are not detected. The method includes contacting a viral polynucleotide that is suspected of being a European-like PRRSV with a primer pair and incubating under conditions to form a detectable amplified polynucleotide. As used herein, a “primer pair” refers to two single stranded polynucleotides that can be used together to amplify a region of a polynucleotide, preferably by a polymerase chain reaction (PCR). The polynucleotide that results from amplifying a region of a polynucleotide is referred to as an “amplification product” or an “amplified polynucleotide.” The phrase “under conditions suitable to form a detectable amplification product” refers to the reactions conditions that result in an amplification product. For instance, in the case of a PCR, the conditions suitable to form a detectable amplification product include the appropriate temperatures, ions, and enzyme.

[0066] One of the primers of the primer pair is complementary to a portion of the viral polynucleotide that corresponds to nucleotides 2268 and 2269 of SEQ ID NO: 1, or the complement thereof. The use of such a primer results in the production of an amplified polynucleotide when there is a deletion. In contrast, the use of such a primer with a European PRRSV will not result in the production of an amplified polynucleotide because there are about 51 nucleotides present between the nucleotides that correspond to nucleotides 2268 and 2269 of SEQ ID NO: 1, or the complement thereof. For instance, the use of such a primer pair will not result in an amplified polynucleotide when the viral polynucleotide is from the Lelystad PRRSV. An example of a primer pair that can be used in this method includes forward primer 5′ATCGGGAATGCTCAGTCCCCTT (SEQ ID NO:12), which corresponds to nucleotides 2,255 to 2,276 of SEQ ID NO:1 and reverse primer Euro2714 5′-GCGCATAAGACAGATCCA (SEQ ID NO:13), which is expected to result in an amplified polynucleotide of about 467 nucleotides. Another primer pair is reverse primer: 5′-AAGGGGACTGAGCATTCCCG (SEQ ID NO:14), which corresponds to the complement of nucleotides 2,257 to 2,276 of SEQ ID NO:1 and forward primer Euro20/5′-CAGAAGGGTTCGAGGAAG (SEQ ID NO:15), which is expected to result in an amplified polynucleotide of about 170 nucleotides.

[0067] In another aspect of detecting a PRRSV by amplification of a polynucleotide, the invention is directed to detecting a virus of the present invention under conditions where both European-like PRRSV and European PRRSV are detected, and the molecular weights of the amplified polynucleotides vary. The primer pair used in this aspect produces an amplified polynucleotide that includes the region of the deletion, i.e., nucleotides 2268 and 2269 of SEQ ID NO: 1, and the corresponding nucleotides of a European PRRSV. When both a European-like PRRSV and European PRRSV are amplified, and the resulting amplified polynucleotides are compared, the amplified polynucleotide that results from the European-like PRRSV will have a molecular weight that is about 51 nucleotides less than an amplified polynucleotide from a European PRRSV. Methods of determining the approximate molecular weight of an amplified polynucleotide are known in the art, and include, for instance, resolving the polynucleotide on an acrylamide or agarose gel.

[0068] An example of a primer pair that can be used in this method includes forward primer Euro1671/5′-GCCTGTCCTAACGCCAAGTAC (SEQ ID NO: 16) and reverse primer/Euro3165-rc: 5′-CATGTCCACCCTATCCCACAT (SEQ ID NO:17), which results in an amplified polynucleotide in a European-like PRRSV of about 1,494 nucleotides, and an amplified polynucleotide in a European PRRSV of about 1,544 nucleotides. Other primer pairs include forward primer Euro20/5′-CAGAAGGGTTCGAGGAAG (SEQ ID NO: 15) and reverse primer/Euro3207 5′-GCTTGGAACTGCGAGG (SEQ ID NO: 19) (expected size of amplified polynucleotide from a European-like PRRSV: about 910 nucleotides); forward primer Euro20/5′-CAGAAGGGTTCGAGGAAG (SEQ ID NO:15) and reverse primer/Euro2714 5′-GCGCATAAGACAGATCCA (SEQ ID NO: 13) (expected size of amplified polynucleotide from a European-like PRRSV: about 616 nucleotides). When these primers are used to amplify a European PRRSV, the size of the amplified polynucleotide is expected to be about 51 nucleotides greater.

[0069] In another aspect of detecting a PRRSV by amplification of a polynucleotide, the invention is directed to detecting a virus of the present invention under conditions where European PRRSV is detected and European-like PRRSV are not detected. In this aspect of the invention, at least one of the primers of a primer pair is complementary a portion of nucleotides 2,419 to 2,470 of the prototype European PRRSV, Lelystad (Genbank Accession number NC_(—)002533), of the complement thereof. An example of a primer pair that can be used in this method includes forward primer Euro1/: 5′-TGAAGGTGCTCTGGTCT (SEQ ID NO:20) and reverse primer/Euro2: 5′-AAATTCCCGCCTACC (SEQ ID NO:21), which results in an amplified polynucleotide from a European PRRSV of about 51 nucleotides.

[0070] The present invention also provides a kit for detecting a virus of the present invention, and a kit for detecting a polypeptide of the present invention or an immunogenic analog or immunogenic fragment thereof. The kit includes an antibody that specifically binds a virus of the present invention, a polypeptide of the present invention or immunogenic analog or immunogenic fragment thereof (when detecting the presence of the virus) or a primer pair as described herein (when amplifying a polynucleotide) in a suitable packaging material in an amount sufficient for at least one assay. Preferably, the antibody does not specifically bind to the European PRRSV deposited as I-1102 with the Collection Nationale De Cultures De Microorganisms, Institut Pasteur, France, or to the North American PRRSV deposited as VR-2332 with the ATCC. The present invention also provides a kit for detecting antibody to a virus of the present invention, a polypeptide of the present invention or an immunogenic analog or immunogenic fragment thereof. When detecting antibody to the virus, polypeptide, or immunogenic analog or immunogenic fragment thereof the kit includes a virus of the present invention, a polypeptide of the present invention or immunogenic analog or immunogenic fragment thereof. Optionally, other reagents such as buffers and solutions needed to practice the invention are also included. Instructions for use of the packaged virus or polypeptide or primer pair are also typically included.

[0071] As used herein, the term “packaging material” refers to one or more physical structures used to house the contents of the kit. The packaging material is constructed by well known methods, preferably to provide a sterile, contaminant-free environment. The packaging material has a label which indicates that the polypeptide or primer pair can be used for detecting a virus of the present invention. In addition, the packaging material contains instructions indicating how the materials within the kit are employed to detect a virus of the present invention. As used herein, the term “package” refers to a solid matrix or material such as glass, plastic, paper, foil, and the like, capable of holding within fixed limits a virus or a primer pair. Thus, for example, a package can be a glass vial used to contain milligram quantities of a primer pair, or it can be a microtiter plate well to which microgram quantities of a virus have been affixed. “Instructions for use” typically include a tangible expression describing the reagent concentration or at least one assay method parameter, such as the relative amounts of reagent and sample to be admixed, maintenance time periods for reagent/sample admixtures, temperature, buffer conditions, and the like.

[0072] The present invention is also directed to vaccines and methods of treatment. Treatment can be prophylactic or, alternatively, can be initiated after the development of MSD in a porcine subject. A vaccine can include, for instance, an immunogenic composition or a neutralizing antibody. The term “vaccine” refers to a composition that, upon administration to a subject, will provide protection against a virus of the present invention. When the vaccine includes an immunogenic composition, administration to the subject will also produce an immunological response to a polypeptide and result in immunity. An immunogenic composition of the present invention can include an attenuated or inactivated virus of the present invention, and/or one or more polypeptides of the present invention or immunogenic analogs or immunogenic fragments thereof, and/or a polynucleotide.

[0073] As used herein, the term “immunogenic composition” refers to a composition or preparation administered in an amount effective to result in some therapeutic benefit or effect so as to result in an immune response that inhibits or prevents MSD in a subject, or so as to result in the production of antibodies to a PRRSV of the present invention. Both local and systemic administration is contemplated. Systemic administration is preferred.

[0074] A polynucleotide used in a vaccine of the invention is preferably one that includes a nucleotide sequence encoding a polypeptide on the present invention, or an immunogenic analog or immunogenic fragment thereof. The polynucleotide can include DNA, RNA, or a combination thereof. The polynucleotide can be supplied as part of a vector or as a “naked” polynucleotide. General methods for construction, production and administration of polynucleotide vaccines are known in the art, e.g. F. Vogel et al., Clin. Microbiol. Rev. 8:406-410 (1995); WO 93/02556; Felgner et al., U.S. Pat. No. 5,580,859, Pardoll et al., Immunity 3:165 (1995); Stevenson et al., Immunol. Rev. 145:211 (1995); Molling, J. Mol. Med. 75:242 (1997); Donnelly et al., Ann. N.Y. Acad. Sci. 772:40 (1995); Yang et al., Mol. Med. Today 2:476 (1996); and Abdallah et al., Biol. Cell 85:1 (1995)). A nucleic acid molecule can be generated by means standard in the art, such as by recombinant techniques, or by enzymatic or chemical synthesis.

[0075] Preferably, administration of a polynucleotide that is part of a vaccine includes the introduction of an expression vector that includes the polynucleotide. There are numerous plasmids known to those of ordinary skill in the art useful for the production of polynucleotide vaccine plasmids, including, for instance, the plasmid pVAX1 as the vector (In Vitrogen Corporation, Carlsbad, Calif.). In addition, the vector construct can contain immunostimulatory sequences that stimulate the animal's immune system. Examples of immunostimulatory sequences include, for instance, sequences with CpG motifs, two 5′ purines, an unmethylated CpG dinucleotide, or two 3′ pyrimidines (see, for instance, Lowie et al., DNA Vaccines Methods and Protocols, Humana Press, Totowa, N.J. (2000)). Other possible additions to the polynucleotide vaccine constructs include nucleotide sequences encoding cytokines, such as granulocyte macrophage colony stimulating factor (GM-CSF) or interleukin-12 (IL-12). The cytokines can be used in various combinations to fine-tune the response of the animal's immune system, including both antibody and cytotoxic T lymphocyte responses, to bring out the specific level of response needed to produce an immune response. Alternatively, the vaccine vector can be a viral vector, including an adenovirus vector, and adenovirus associated vector, or a retroviral vector.

[0076] Immunogenic carriers can be used to enhance the immunogenicity of a vaccine that includes an immunogenic composition. Such carriers include but are not limited to other polypeptides, polysaccharides, liposomes, and bacterial cells and membranes. Polypeptide carriers may be joined to the attenuated or inactivated virus of the present invention, and/or a polypeptide of the present invention or an immunogenic analog of immunogenic fragment thereof to form fusion polypeptides by recombinant or synthetic means or by chemical coupling. Useful carriers and means of coupling such carriers to polypeptide antigens are known in the art.

[0077] The vaccine preferably includes a pharmaceutical carrier that is compatible with a porcine subject. The vaccine may be delivered orally, parenterally, intranasally or intravenously. Factors bearing on the vaccine dosage include, for example, the age, weight, and level of maternal antibody of the infected pig. The vaccine doses should be applied over about 14 to 28 days to ensure that the pig has developed an immunity to the MSD infection.

[0078] The vaccine of the present invention can be administered in a variety of different dosage forms. An aqueous medium containing the vaccine may be desiccated and combined with pharmaceutically acceptable inert excipients and buffering agents such as lactose, starch, calcium carbonate, sodium citrate formed into tablets, capsules and the like. These combinations may also be formed into a powder or suspended in an aqueous solution such that these powders and/or solutions can be added to animal feed or to the animals' drinking water. These compositions can be suitably sweetened or flavored by various known agents to promote the uptake of the vaccine orally by the pig.

[0079] For purposes of parenteral administration, the composition can be combined with pharmaceutically acceptable carrier(s) well known in the art such as saline solution, water, propylene glycol, etc. In this form, the vaccine can be parenterally, intranasally, and orally applied by well-known methods known in the art of veterinary medicine. The vaccine can also be administered intravenously by syringe. In this form, the vaccine is combined with pharmaceutically acceptable aqueous carrier(s) such as a saline solution. The parenteral and intravenous formulations of the composition may also include emulsifying and/or suspending agents as well, together with pharmaceutically acceptable diluent to control the delivery and the dose amount of the composition.

[0080] The present invention is illustrated by the following examples. It is to be understood that the particular examples, materials, amounts, and procedures are to be interpreted broadly in accordance with the scope and spirit of the invention as set forth herein.

EXAMPLES Example 1 Detection of Virus in Infected Pigs

[0081] This example describes the isolation of a new PRRSV from infected pigs. The PRRSV was given the designation MND99-35186 and is referred to in these examples as European-like.

[0082] Methods

[0083] Three live, 3 to 4-day-old pigs from a herd with a clinical history of late-gestation abortions and weak-born pigs were submitted to the Minnesota Veterinary Diagnostic Laboratory (St. Paul, Minn.). The pigs were euthanized by intravenous over dose of barbiturate and necropsied (autopsied).

[0084] Portions of lung, lymph nodes, brain, spleen, kidney, tonsil and heart were collected and pooled as one sample. The sample was treated for the isolation of porcine reproductive and respiratory syndrome virus (PRRSV), pseudorabies virus (PRV), and swine influenza virus (SIV).

[0085] For isolation of PRRSV, samples were inoculated on MARC-145 cells and primary porcine alveolar macrophages. Before inoculation, the samples were treated as described by Rossow et al. (Vet. Pathol., 32, 361-373 (1995)). Briefly, Hank's Balanced Salt Solution was added to the tissue sample or sera to make an approximately 10% (vol/vol) suspension, and then homogenized. The homogenate was centrifuged a 4,133×g for 20 minutes, and the supernatant removed and saved. The pelleted material was discarded. The conditions for inoculating MARC-145 cells and primary porcine alveolar macrophages are described below. In addition, serum from each pig was pooled together into one sample and then used to inoculate MARC-145 cells and primary porcine alveolar macrophages.

[0086] Portions of lung, lymph nodes, stomach, brain, liver, kidney, tonsil, heart and ileum (a section of the small intestine) were preserved in 10% formalin buffered with a mixture of dibasic sodium phosphate and monobasic sodium phosphate to yield pH 7.0. The tissues were incubated in the formalin for at least 12 hours before subsequent use in assays. Portions of each tissue were paraffin embedded.

[0087] Formalin fixed tissues were stained by hematoxylin and eosin (H and E) staining.

[0088] Formalin fixed tissues were also assayed for PRRSV testing by immunohistochemical technique by the method of Christopher-Hennings et al., (Vet. Pathol, 35, 260-267 (1998)). Briefly, formalin fixed, paraffin embedded lung was sectioned at approximately 4 microns and sections were applied to glass slides. Tissue sections were covered with the monoclonal antibody SDOW-17 and incubated in a humidified chamber. SDOW-17 is an anti-PRRSV monoclonal antibody that recognizes an epitope present on the Lelystad PRRSV and on the VR-23332 PRRSV. Antibody binding to PRRSV in the lung was identified using a modified avidin biotin complex method (Hsu et al., J. Histochem. Cytochem., 29, 577-580 (1981)).

[0089] Lung sections were rapidly frozen in isopentane at −30° C. The frozen sections were examined for PRRSV by direct fluorescent antibody technique using the monoclonal antibody SDOW-17. Direct FA examination of tissue was done by the method of Rossow et al. (Vet. Pathol., 32, 361-373 (1995)). Briefly, tissues were frozen, sectioned at approximately 5 microns and transferred to glass slides. Tissue sections were covered with fluoroscene-conjugated SDOW-17, an anti-PRRSV monoclonal antibody (obtained from E. Nelson, South Dakota State University, South Dakota). The tissue sections were then incubated in a humidified chamber for about 1 hour, and excess unbound antibody removed by washing in phosphate buffered saline. The presence of antibody binding to PRRSV in the lung was visualized with a fluorescent microscope.

[0090] Brain, lung, and liver samples were cultured on blood agar plates to detect the presence of aerobic bacteria.

[0091] Pooled tissues were also examined for leptospira using the method of Smith et al. (Cornell Vet., 57, 517-526 (1967)).

[0092] Results

[0093] PRRSV was identified in lung sections from each pig by immunohistochemical and direct fluorescent antibody.

[0094] Light microscopic tissue lesions (H and E slides) were compatible with PRRSV infection. Histopathology of the lungs showed diffuse septal thickening by macropahges. Some alveoli contained necrotic cell debris. Lymph nodes were characterized by germinal centers filled with blast-lymphocytes and small foci of necrosis. The muscular layer in one stomach was characterized by lymphoplasmacytic perineuritis and perivasculitis. Brain, liver, kidney, tonsil, heart, and ileum did not have lesions.

[0095] Tests for PRV and SIV were negative and no bacterial pathogens were identified in tissues from the infected pigs.

[0096] PRRSV was isolated from pooled tissue homogenate and pooled sera cultured in the alveolar macrophages. However, few cells were infected with PRRSV. No PRRSV was isolated from either sample cultured in MARC-145 cells.

[0097] Because this PRRSV grew poorly in the alveolar macrophages, 3 to 4-week-old pigs from a documented PRRSV-free farm were inoculated (intramuscularly and intranasally) with approximately 1 ml of the virus obtained from the supernatant from the infected alveolar macrophages. The virus was diluted by adding about 9 mls of Hanks Balanced Salt Solution to about 1 ml of virus-containing supernatant. Clinically, the experimentally infected pigs exhibited the same symptoms of mild, transient signs of lethargy within about 1-2 days that are also seen after infection of a pig with Lelystad virus or VR-2332. Each infected pig seroconverted to the PRRSV infection. Seroconversion was measured by the IDEXX Elisa test (HerdChek-PRRSV, IDEXX Laboratories Inc. Westbrook, Me.). Seroconversion was also measured by indirect fluorescent antibody test using Lelystad infected cells and the method of Yoon et al. (J. Vet. Diagn. Invest., 4, 144-147 (1992)). The European-like PRRSV was re-isolated from infected pig tissues and serum, cultured in porcine alveolar macrophages, and identified in tissues by immunohistochemistry.

Example 2 Infection of Porcine Alveolar Macrophages with PRRSV

[0098] Porcine alveolar macrophages were isolated by collection from PRRSV-negative pigs less than 6-weeks-old. Pigs were euthanized, and trachea and lungs removed and airways lavaged with sterile phosphate buffered saline. The phosphate buffered saline was made by combining 8.5 grams NaCl, 1.1 grams disodium phosphate, and 0.32 gram sodium monophosphate in 10 liters distilled water. The Porcine alveolar macrophages were concentrated by centrifugation, confirmed negative for PRRSV by isolation and examination using direct fluorescent antibody as described in Example 1, and used immediately or stored in liquid nitrogen at a concentration of 10⁶ cells/ml. Frozen alveolar macrophages chould be used within 6 months.

[0099] Freshly harvested porcine alveolar macrophages (about 10⁷) or frozen cells (10⁶ cells) were plated on a 1×48 well plate or a 1×75 cm flask, and allowed to adhere for 4 hours to overnight in about 10 to 25 ml RPMI-1640 complete medium. The cells cannot be allowed to incubate for more than one day before virus is added. RPMI-1640 complete medium is made by combining 500 ml RPMI-1640 medium containing 300 mg/liter L-glutamine, 25 mM HEPES [N-(2-Hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid)] (Catalog #10-041-CV, Mediatech Inc., Herndon. Va.), 40 ml heat-inactivated Fetal Bovine Serum (Cat #12133-78P; JRH Bioscience, Inc., Lenexa, Kans.), 1 gram neomycin sulfate (Gibco Life Technologies, Rockville, Md.), 40 ml Hanks Balanced Salt Solution (HBSS) (Gibco Life Technologies, #14180053, Rockville, Md.) containing neomycin sulfate at a final concentration of 150 μg/ml medium), 66 ml HBSS containing penicillin G potassium salt (Sigma #P7794, St. Louis, Mo.), streptomycin sulfate (Sigma #S9137), and amphotericin B solubilized (Sigma A-9528) at a final concentration of 2500 U penicillin G, 0.45 mg streptomycin sulfate/ml medium, and 120 μg/ml amphotericin B/ml of medium.

[0100] The medium was removed, and the cells were washed in once ins HBSS, and the cells were infected with 1 ml of virus in 1 ml RPMI incomplete medium (same as RPMI complete but without FBS added). The virus titer can vary, and when the virus is from tissue isolated from a PRRSV-infected pig, is unknown. HBSS was 500 mls HBSS supplemented with 5 mls of 100×neomycin (10 mg/ml) and 5 mls of 100×pennecillin (10,000 U ml), streptomycin (10 mg/ml), and fungizone (25 μg/ml).

[0101] The plate was gently rotated for 1 hour at room temperature. Nine mls of RPMI complete medium were added and the infected cells were incubated at 37° C. The cell were observed daily until 60-80% cytopathic effect (CPE) was seen (2-3 days). CPE appears as fragmented, vacuolated, malformed, shrunken cells.

[0102] Virus was isolated by removing the medium and centrifuging at about 4,000×g for 10 minutes to remove cellular debris, and leave the virus in the supernatant.

[0103] The presence of PRRSV in the primary porcine alveolar macrophages was confirmed by staining with the SDOW-17 monoclonal antibody as described by Nelson et al. (J. Clin. Microbiol., 34, 3184-3189 (1993)).

Example 3 Sequence Analysis of Virus

[0104] 1. PRRSV RNA Extraction:

[0105] Viral RNA was extracted from macrophage culture supernatants using QIAamp Viral RNA Mini Spin Kit (QIAgen, Inc., Valencia, Calif.). Briefly, 280 μl cell culture fluid was added to 1120 μl Buffer AVL/Carrier RNA, pulse vortexed for 15 seconds, incubated at room temperature for 10 minutes, and centrifuged briefly. After this step, 1120 μl 100% ethanol was added to the reaction, pulse vortexed for 15 seconds, and centrifuged briefly. The reaction was then applied to a QIAamp spin column (in a 2 ml collection tube) in 630 μl aliquots (4×) and centrifuged at 6000×g (800 rpm) for 1 minute, discarding flow-through each time. When all sample was applied to the filter, the QIAamp spin column was placed into a clean 2 ml collection tube, and again centrifuged. Buffer AW1 (500 μl) was added to the filter containing viral RNA, and this reaction was centrifuged at 6000×g (8000 rpm) for 1 minute. Buffer AW2 (500 μl) was added to the spin column and the column was centrifuged at full speed (20,000×g; 14,000 rpm) for 3 minutes. The collection tube was discarded, and the QIAamp spin column was place in a clean 1.5 ml centrifigue tube. Buffer AVE (60 μl) was added to the spin column, the column incubated at room temperature for 1 minutes, and then centrifuged at 6000×g (8000 rpm) for 1 minutes.

[0106] 2. RT-PCR: Two methods were used to reverse transcribe the viral RNA and obtain DNA for use in DNA sequence analysis. In general, the primers were selected to hybridize to an appropriate portion of SEQ ID NO: 1 and amplify a DNA fragment that was then used in DNA sequencing reactions.

[0107] a. Qiagen OneStep RT-PCR:

[0108] Five microliters of extracted RNA were added to a reaction mix containing 1×Qiagen RT-PCR Buffer; 400 nM of each DATP, dCTP, dGTP and dTTP; 0.08 units/reaction RNase inhibitor (20 U/μl, Perkin Elmer, Boston Mass.); {fraction (1/25)} volume of Qiagen Enzyme mix; 300 nM each forward and reverse primer; to make a total reaction volume of 25 ml. The thermocycling conditions consisted of: 1 cycle 50° C. for 30 minutes; 1 cycle of 95° C. for 15 minutes; 35 cycles of 57° C. for 30 seconds, 72° C. for 45 seconds, 94° C. for 45 seconds; 1 cycle of 57° C. for 30 seconds; 1 cycle of 72° C. for 10 minutes and a 4° C. hold.

[0109] b. RT and PCR-2 Step Reaction

[0110] b1. Reverse Transcription: Random primed cDNA was generated in the following way: 2 μl of 50 μM random hexamers were added to 6 μl of RNA extract. This was heated to 70° C. for 5 minutes and quickly chilled on ice. Then 32 μl of a master mix containing 5 mM MgCl₂ (Perkin Elmer), 1×Perkin Elmer Buffer II (50 mM KCl, 10 mM Tris-HCl, (pH 8.3 at room temperature)), 1 mM dNTPs (Perkin Elmer), 1 U/μl RNase Inhibitor (20 U/μl, Perkin Elmer), and 25 U/μl MuLV RT (murine leukemia virus reverse transcriptase; Perkin Elmer). The thermocyling conditions consisted of: 1 cycle of 22° C. for 10 minutes; 1 cycle of 42° C. for 15 minutes; 1 cycle of 95° C. for 10 minutes, 1 cycle of 5° C. for 5 minutes and hold at 4° C.

[0111] b2. PCR: Reactions tube containing 40 μl of 5 mM MgCl₂ (Perkin Elmer), 1×Perkin Elmer Buffer II, 300 nM forward primer, 300 nM reverse primer, and 0.25 U/μl Amplitaq Polymerase (Perkin Elmer) was added to 10 μl cDNA obtained from the reverse transcription (paragraph b1, above). Alternatively, to amplify longer section of random primed cDNA, Expand Long Template PCR Kit (Boehringer Mannheim, Indianapolis, Ind.) was used. The thermocycling conditions consisted of: 1 cycle of 93° C. for 4 minutes; 35 cycles of 57° C. for 30 seconds, 72° C. for 45 seconds, 93° C. for 45 seconds; 1 cycle of 57° C. for 30 seconds; 1 cycle of 72° C. for 10 minutes and a 4° C. hold. (Annealing temperature would vary according to the primer pair utilyzed to amplify cDNA).

[0112] 3. The Results of Each PCR were Evaluated and Prepared for DNA Sequencing.

[0113] Sequence analysis was performed by the Advanced Genetic Analysis Center (AGAC) (University of Minnesota, Minneapolis, Minn.). using an ABI Model 377 DNA Sequencer.

[0114] I. Evaluation of PCR Reactions on an Agarose Gel.

[0115] One gram of agarose was added to 100 ml of 1×TAE buffer. This was microwaved for 2 minutes, and 4 μl of 10 mg/ml EtBr was added to every 100 ml agarose. The gel was cast and allowed to solidify for about 15-30 minutes. Four μl of PCR product were mixed with 1 μl loading dye and added to the gel, which was run at 140 volts for 1 hour or 75 volts for 2 hours.

[0116] II. Purification of PCR Product with Qiagen Qiaquick PCR Purification Kit

[0117] For each sample to be purified, a column was placed into a collection tube. One hundred μl PB buffer were added to the 20 μl PCR reaction left in PCR tube, and mixed thoroughly. All of the PCR product/PB buffer mix was added to the column, and the column was spun for 1 minute at full speed in an Eppendorf microfuge. The flow-through from collection tube was discarded, and the column was placed back in the tube. Seven hundred and fifty μl of PE buffer was added, and the column spun for another minute at full speed. After discarding the flow-through from collection tube, the column was spun for another minute at full speed to remove any residual PE buffer from the column. The column was transferred into a clean, microfuge tube, and 30 μl H₂O was added to the column and incubated for at least a minute at room temp. The column was spun for one minute at full speed. The PCR product/H₂O eluate in the microfuge tube and was ready to be added to the sequencing reaction.

Example 4 Detection of European-like PRRSV

[0118] In this example, viral DNAs were amplified using primers that amplify European-like PRRSV, European PRRSV, and North American PRRSV. The amplified region included the deletion that is present in European-like PRRSV.

[0119] The viral RNA of Lelystad was obtained from supernatants of infected MA-104 cells, the viral RNA of VR-2332 was obtained from supernatants of infected MA-104 cells, and the viral RNA from European-like PRRSV was obtained from supernatants of infected primary porcine alveolar macrophages, cDNA of viral RNA was prepared as described above in Example 3.

[0120] The viral cDNAs were amplified using the primers Euro1671/: 5′-GCCTGTCCTAACGCCAAGTAC (SEQ ID NO:16) and/Euro3165-rc: 5′-CATGTCCACCCTATCCCACAT (SEQ ID NO:17). The amplification conditions are listed in Table 2. TABLE 2 General PCR Conditions (for 50 uL reaction) Stock Component Concentration Final Cone MgCl₂ 25 mM   5 mM Buffer II¹ 10 X   1 X Forward Primer 15 uM  0.3 uM Reverse Primer 15 uM  0.3 uM Taq Polymerase  5 U/ul 0.25 U/ul

[0121] Results

[0122] Amplification of viral DNA from Lelystad, VR-2332, and European-like resulted in amplification products that migrated at the predicted molecular weights. As expected, the product of amplifying the European-like DNA migrated at about 1.5 kilobases, approximately 51 base pairs less than Lelystad.

[0123] The complete disclosure of all patents, patent applications, and publications, and electronically available material (e.g., GenBank amino acid and nucleotide sequence submissions) cited herein are incorporated by reference. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described for variations obvious to one skilled in the art will be included within the invention defined by the claims.

[0124] All headings are for the convenience of the reader and should not be used to limit the meaning of the text that follows the heading, unless so specified. Sequence Listing Free Text SEQ ID NO: 1 Portion of nucleotide sequence of a porcine repro- ductive and respiratory syndrome virus SEQ ID NOs: 2-10 Polypeptides predicted from open reading frames of SEQ ID NO: 1. SEQ ID NO: 11 Nucleotides 1,981 to 2,820 of the Lelystad virus SEQ ID NOs: 12-17 Primer SEQ ID NO: 18 Oligonucleotide SEQ ID NOs: 19-21 Primer

[0125]

1 21 1 14896 DNA Porcine reproductive and respiratory syndrome virus 1 cttgttgtgg ggaggaactc ccgaggattt tcggagagga cctgctttac tggatgttca 60 ccctttaacc atgtgtggga gcgtctcccg gtgcatgtgc accccggctg tccgggtatt 120 ttggaacgcc ggccaagtct tttgcacacg gtgtgtcagt gcgcgggctc ttctctctcc 180 agagcttcag gacactgacc tcggtgcggt tggattgttt tacaggccta gggataagct 240 acactggaaa gtccctatcg gcatccccca ggcggaatgt actccatccg ggtgctgttg 300 gctctcagct gtattccctt tggcgcgcat gacctctggc aatcacaact tccttcaacg 360 acttgttaag gttgctgatg ttttgtaccg tgacggttgc ctggcacctc gacacctccg 420 tgagcttcaa gtttacgagc gcggctgcaa ctggtaccca atcacggggc ccgtacccgg 480 gatgggtttg tttgcgaatt ccatgcacgt atccgaccag ccgttccctg gtgccaccca 540 tgtgttgact aactcgcctc tacctcaaca ggcgtgtcgg caaccgttct gtccatttga 600 ggaagctcat tctggcgtgt ataggtggaa gaaatttgta attttttcgg actcccctct 660 caacggccaa tctcgcatta tgtggacgcc gaaatccgat gattcagctg ctctggagga 720 actaccgcct gagttagaac gtcaggttga aattctcatt cggagtttcc ctgctcatca 780 ccctgtcaac ctggcggact gggagctcac tgggtctcct gagaacggtt tttccttcaa 840 cacgtctcat tcttgcggtc atctcgtccg aaactccaac gtgtttgatg gcaagtgctg 900 gctcacctgc tttttgggcc agtcggtcga agtgcgctgc catgaagaac atctagccaa 960 cgccttcggt taccaaacca agtggggcgt gcacggtaag taccttcaac gcaggcttca 1020 agttcgcggc attcgtgctg tagtcgatcc tgacggcccc attcacgttg aagcgctgtc 1080 ttgctcccag tcttggatca ggcacctgac cctgaatgac gatgtcaccc caggatttgt 1140 tcgcctgaca tccattcgca ttgtgccgaa tacagagcct accacttccc agatctttcg 1200 atttggagcg cataagtggt atggcgctgc cggtaaacgg gctcgtgcca agcgtaccgc 1260 taaaggtggg aaggattctg ttcccgctct caaggttgcc ctgccggtcc ccgcctgtgg 1320 aataaccacc tattccccac cgacagacgg gtcttgtggt tggcatgtcc ttgccgccat 1380 aatgaaccgg atgatgaacg atgacttcac gtcccctctg actcagtaca acagaccaga 1440 ggatgattgg gcttcagatt atgatcttgc tcaggcgatt caatgtctac aactacctgc 1500 taccgtggtt cggaatcgcg cttgtcctaa cgccaagtac cttataaaac ttaacggggt 1560 tcactgggag gtagaggtga gatctggaat ggctcctcgc tccctttctc gtgaatgtgt 1620 ggtcggcgtt tgttctgaag gctgcgtcgc gccgccttac ccagcggatg ggcttcctaa 1680 gcgtgcactc gaggccttgg cgtctgctta cagactaccc tccgattgtg tttgctctgg 1740 tattgctgac tttcttgcca atccacctcc tcaagaattc tggactctcg acaaaatgtt 1800 gacctccccg tcaccagaac ggtccggctt ctctagtttg tataacttgc tattagaggt 1860 tgttccgcaa aaatgcggtg tcacggaagg ggccttcacc tatgctgttg agaggatgtt 1920 aatggattgt ccgagctccg aacaggccat ggctcttctg gcaaaaatta aagttccatc 1980 ctcaaaggcc ccatctgtgt ccttggacga gtgtttccct gcagatgttc cggccgattt 2040 cgagccaacg tctcagaaaa ggccccaaag ttccggcgcc gctgtcgccc tgtgttcatc 2100 ggatgcagaa gggttcgagg aagcagcccc agaaggagtt caagagagag gccataaggc 2160 cgtccactct gcactctttg ccaagggtcc aaataacgaa caggtacagg tggttgccgg 2220 tgagcaacag aagctcggcg gttgtggttt ggcaatcggg aatgctcagt cccctttaaa 2280 ttccatgaaa gaaaacatgc gcagtagccg ggaagacgaa ccactggatt tgtcccaacc 2340 agcaccagtt gccgcaacga cccttgagag agagcaaaca cccgataacc caggttctga 2400 tgccggtgcc ctccccgcca ccgttcgaga atctgtcccg acagggccta tgctccgtca 2460 tgttgagcac tgtggcacgg agtctggcga tagcagttcg cctttggatc tgtcttatgc 2520 gcaaactttg gaccagcctt tagatctatc cctggccgtt tggccggtga aggccaccgc 2580 gtctgaccct ggctgggtcc acggtaggcg cgagcctgtc tttgtaaagc ctcgaaaagc 2640 tttctctgat agcgactcag cctttcagtt cgggaagctt tctgagtccg gctctgtcat 2700 tgagtttgac cgaacaaaag atgctccggt ggttgacgcc cctgttggct cgacgacttc 2760 gaacgaggca ctgtctatag ccgatccttt cgaatttgcc gaactcaagc gcccgcgttt 2820 ctccgcacaa gccttaattg accgaggcgg tccgcttgcc gatgtccatg cgaaaataaa 2880 gaaccgggtg tatgaacggt gcctccaagc ttgtgagccc ggtagtcgtg caaccccagc 2940 caccaaggag tggctcgaca agatgtggga tagggtggac atgaaaactt ggtgctgcac 3000 ctcgcagttc caagctggtc gcattcttgc gtccctcaaa ttcctccctg acatgattca 3060 agacacaccg cctcctgttc ccaggaagaa ccgagctagt gacaatgccg atctgaagca 3120 actggtggca cagtgggata ggaaattgag tatgacccct ccccaaaaac cggttgagcc 3180 agtgcttgac cagaccgtct ctccgcctac ggatactcag caagaagatg tgaccccctc 3240 cgatgggcca ccccatgcgc cggattttcc cagtcgtgtg agcacgggcg ggagttggaa 3300 agaccttatg tgttccggca cccgtctcgc ggggtctatc agtcagcgcc tcatgacatg 3360 ggtttttgaa gttttctccc acctcccagc ctttatgctc acacttttct cgccgcgggg 3420 ctctatggct ccaggtgatt ggttgtttgc aggtgttgtt ttacttgctc tcttgctctg 3480 tcattcttac ccgatactcg ggtgccttcc cttattgggt gtcttttctg gttctttgcg 3540 gcgtgttcgt ctgggtgttt ttggttcttg gatggctttt gctgtatttt tattctcgac 3600 tccatccaac ccagtcggtt cttcttgtga ccacgattcg ccggaatgtc atgctgagct 3660 tttggctctt gagcagcgcc aactttggga acctgtgcgc ggccttgtgg tcggcccctc 3720 gggcctctta tgtgtcattc ttggcaagtt actcggtggg tcacgttatc tctggcatat 3780 tctcctacgt ttatgcatgc ttacagattt ggccctttct cttgtttatg tggtgtccca 3840 agggcgttgt cacaagtgtt ggggaaagtg tataagaaca gctcctactg aggtggctct 3900 taatgtgttt cctttcacgc gcgccacccg ttcctctctt gtatccttgt gtgatcgatt 3960 ccaaacgcca aaaggggttg atcctgtgca cttggcaacg ggttggcgcg ggtgctggcg 4020 tggtgggagt cccgtccatc aaccacacca aaagcccatt gcttatgcca acttggatga 4080 aaagaaaata tctgcccaaa cggtggttgc cgtcccatac gatcccagtc aggccatcaa 4140 atgcctgaaa gttctgcagg cgggaggggc tatcgtggac cagcctacac ctgaggttgt 4200 tcgtgtgtcc gaaatcccct tctcagctcc attttttcca aaagttccag tcaacccaga 4260 ttgcagagtc gtggtagatt cggacacttt tgtggctgcg gttcgatgcg gttactcgac 4320 agcacaactg gtcttgggcc agggcaactt tgccaagttg aatcagaccc cccccaggaa 4380 ctccacttcc accaaaacga ctggtggggc ctcttacacc cttgctgtgg ctcaagtaac 4440 tgtgtggact ctttttcatt tcatcctcgg cctttggttt acatcacctc aagtgtgtgg 4500 ccgaggaacc gctgacccat ggtgttcaaa tcctttttca taccccacct atggccctgg 4560 agttgtgtgc tcctctcggc tttgcgtgtc tgccgacggg gtcaccttgc cattgttctc 4620 agccgtggca caactttccg gtagagaggt ggggatcttt attttggtgc tcgtttcctt 4680 gattgccttg gcccaccgta tggctcttaa ggcagacatg ttagtcgtct ttttggcttt 4740 ttgtgcttac gcctggccta tgagctcctg gttaatttgc ttctttccct tactcttgaa 4800 gtgggtcacc cttcaccctc tcaccatgct ttgggtgcac tcattcttgg tgttttgtct 4860 gccagcggcc ggcatcctct cattagggac aactggcctt ctctgggcaa ttggccgctt 4920 tacccaggtt gccggaatta ttacacctta tgacatccac caatacacct ctgggccacg 4980 tggtgcagct gctgtggcca cagccccaga aggcacttat atggccgccg tccggagagc 5040 tgctttaact gggcgaactt taatcttcac cccgtctgca gttggatccc ttctcgaagg 5100 tgccttcagg actcaaaaac cctgccttaa caccgtgaat gttgtaggct cttcccttgg 5160 ttccggaggg gttttcacca ttaacggcag aaggactgtc gtcactgctg ctcatgtgtt 5220 gaacggtgac acagctagag tcaccggcga ctcctacaac cgcatgcaca ctttcaagac 5280 caatggtgat tatgcctggt cccatgctga tgactggcag ggcgttgctc ctgtggtcaa 5340 ggttgcgaag gggtaccgcg gtcgtgccta ctggcaaaca tcaactggtg tcgaacccgg 5400 cattattggg gaagggttcg ccttctgttt caccaactgt ggcgattcag ggtcacctgt 5460 tatctcagaa tctggtgatc tcattggaat ccacactggt tcaaacaaac tcggttctgg 5520 tcttgtgacg acccctgaag gggagacctg cgccatcaaa gaaaccaagc tctctgacct 5580 ttccagacat tttgcaggcc cgagcgttcc tcttggggac attaagttga gtccggccat 5640 catccctgat gtgacatcca ttccgagtga cttggcatcg ctcctagcct ccgtccctgt 5700 attggaaggc ggcctctcga ccgtccaact tctgtgtgtc tttttcctcc tctggcgcat 5760 gatgggccat gcctggacac ccattgtcgc cgtgggcttc tttctactaa atgaaatcct 5820 tccagcagtt ttggtccgag ccgtgttttc ttttgcactc tttgtgcttg catgggtcac 5880 cccctggtct gcgcaggtgt tgatgattag gctcctcacg gcatctctca accgcaacaa 5940 gttctctctg gcgttctacg cactcggggg tgtcatcggt ttggccgctg aaattgggac 6000 ttttgctggt agactgcctg aattgtctca agccctttcg acatactgtt tcttacctag 6060 ggttcttgcc atggccagtt gtgttcccat catcatcatt ggtggactcc ataccctcgg 6120 tgtgattctg tggttgttca aataccggtg cctccacaac atgctggttg gtgatgggag 6180 tttttcaagc gccttcttcc tacggtattt tgcagagggt aatttgagaa aaggtgtttc 6240 acagtcctgt ggcatgaata acgagtccct gacggctgct ctagcttgca agttgtcgca 6300 agctgacctt gattttttgt ccagcttaac gaacttcaag tgctttgtat ctgcttcaaa 6360 catgaaaaat gccgctggcc agtacattga agcagcttat gccagggccc tacgccaaga 6420 gttggcctct ctagttcagg ttgacaagat gaaaggagtt ttgtccaagc tcgaggcctt 6480 tgctgaaaca gccaccccgt cccttgacac aggtgacgtg gttgttctgc ttgggcaaca 6540 tcctcacgga tccatcctcg atattaatgt ggggactgaa aggaaaactg tgtccgtgca 6600 agagacccgg agccttggcg gctccaaatt cagtgtttgc actgttgtgt ccaacacacc 6660 cgtggatgcc ttaaccggca tcccactcca gacaccaacc cctctttttg agaatggtcc 6720 gcgtcatcgc agtgaggaag acgatcttaa agtcgagagg atgaagaaac actgtgtgtc 6780 cctcggcttt cacaacatca atggcaaagt atactgcaaa atctgggata agtctaccgg 6840 tgacaccttt tacaccgatg attcccggta tacccaagac tatgcttttc aggacaggtc 6900 agccgactac agagacaggg actatgaagg tgtgcaaacc gccccccaac agggctttga 6960 tccaaagtct gaaacccctg ttggcactgt agtgatcggc ggtattacgt ataataggta 7020 cctgatcaaa ggtaaggaga tcctggttcc caagcctgac aactgccttg aagctgccaa 7080 gctgtccctt gagcaagctc tcgctgggat gggtcaaact tgtgacctca cagctgccga 7140 ggtggaaaag ctaaagcgta tcattagtca actccaaggt ttgaccactg aacaggcttt 7200 aaactgttag ccgccagtgg cttgacccgc tgtggccgcg gcggcttagt tgtaactgaa 7260 acggcggtaa aaattgtaaa ataccacagc agaactttca cctttggccc tcttgacctg 7320 aaagttactt ccgaggcgga ggtaaagaaa tcaactgagc agggccacgc tgttgtggca 7380 aacttatgtt cgggtgtcat cttgatgaga cctcacccac cgtcccttgt tgacgttctt 7440 ctgaaacccg gacttgacac aaaacccggc attcaaccag ggcatggggc cgggaatatg 7500 ggcgtggacg gttctatgtg ggattttgaa accgcaccca caaaggcaga actcgagtta 7560 tccaagcaaa taattcaagc atgtgaagtt aggcgcgggg acgccccgaa cctccaactt 7620 ccttataagc tctatcctgt taggggggat cctgcgcggc atgggggccg ccttatcaat 7680 accaggtttg gagatttatc ttacaaaact cctcaagaca ccaagtccgc aatccacgcg 7740 gcttgttgcc tgcaccccaa cggggcccct gtgtctgatg gtaaatcaac actaggtacc 7800 actctccaac atggtttcga gctttatgtc cccactgtac cttatagtgt catggagtac 7860 ctcgattcac gccctgacac cccttttatg tgtactaagc atggcacttc caaggctgct 7920 gcagaggacc tccaaaaata cgacctgtcc actcagggat tcgtcctgcc tggggtctta 7980 cgcctagtac gtagattcat ctttggccat attggtaagg cgccgccatt gttccttcca 8040 tcaacctatc ccgccaaaaa ctctatggca gggatcaatg gccagaggtt tccaacaaag 8100 gacgttcaga gcatacctga aattgatgaa atgtgtgccc gcgccgtcaa ggagaattgg 8160 caaactgtga caccttgtac tctcaagaaa cagtactgtt ccaagcccaa aaccaggacc 8220 atcctgggca ccaacaactt tattgccttg gctcacagat cggcgctcag tggtgtcacc 8280 caggcattca tgaagaaggc ctggaagtcc ccaattgcct tgggaaaaaa caaattcaag 8340 gagctgcatt gcaccgtcgc cggcaggtgt cttgaggccg acttggcctc ctgtgaccgc 8400 agcacccccg ccattgtaag atggttcgtc gccaacctcc tgtatgaact tgcaggatgt 8460 gaagagtact tgcctagcta tgtgcttaat tgctgccatg accttgtggc aacacaggat 8520 ggtgccttca caaaacgcgg tggcctgtcg tccggggacc ccgtcaccag tgtgtccaac 8580 accgtatatt cactggtgat ttatgcccag cacatggtgt tgtcggcctt gaaaatgggt 8640 catgaaatcg gtctcaagtt cctcgaggaa cagctcaaat ttgaggacct cctcgaaatt 8700 cagcctatgc tggtatactc tgatgacctt gtcttgtacg ctgaaagacc cacttttcct 8760 aattaccact ggtgggtcga gcaccttgac ctaatgctgg gtttcagaac ggacccaaag 8820 aaaactgtca taactgataa acccagcttc ctcggctgca gaattgaggc agggcgacag 8880 ctggttccca atcgcgaccg catcctggct gctctcgcat accacatgaa ggcgcagaac 8940 gcctcagagt attatgcgtc tgctgccgca atcctgatgg attcatgcgc ttgcattgac 9000 catgaccctg agtggtatga ggacctcatc tgcggtattg cccaatgcgc ccgccaggat 9060 ggttatagct tcccaggtcc ggcatttttc atgtccatgt gggagaggct gagaagtcat 9120 aatgaaggga agaaatttcg ccactgcggc atctgcgatg ccaaagctga ctatgcatcc 9180 gcctgtgggc ttgatttgtg tttgtttcat tcgcactttc atcaacactg tcctgtcact 9240 ctgagctgcg gtcatcatgc cggttcaagg gaatgttcgc agtgtcagtc acctgttggg 9300 gctggcagat cccctcttga tgccgtgtta aaacaaattc catataaacc tcctcgtact 9360 gtcatcatga aggtgggtaa caaaacaacg gctctcgatc cggggaggta ccaatcccgt 9420 cgaggtctcg ttgcagtcaa gagaggtatt gcaggcaatg aggttgatct ttccgatgga 9480 gactaccaag tggtgcctct tttgccgact tgcaaagaca taaacatggt gaaggtggct 9540 tgtaatgtac tactcagtaa gttcatagtg gggccaccag gttccggaaa gaccacctgg 9600 ttactaggtc aagtccagga cgatgatgtc atttacacac ccacccatca gactatgttt 9660 gatatagtca gtgctctcaa agtttgcagg tataccatcc caggagcctc aggacttcct 9720 ttcccaccac ccgccaggtc cggaccgtgg gttaggctca tagccagcgg gcacgtccct 9780 ggccgagtat catacctcga tgaggctgga tactgtaatc atttggacat tctcagactg 9840 ctctccaaaa caccccttgt gtgtttgggt gaccttcaac aacttcaccc tgtcggcttt 9900 gattcctact gttatgtgtt tgatcagatg cctcagaagc aactgaccac catttacaga 9960 tttggcccta acatctgcgc ggccattcag ccttgctaca gggagaagct tgaatctaag 10020 gctaggaaca ccagggtggt ttttaccacc cggcctgtgg cctttggtca ggtgctgaca 10080 ccataccata aagatcgcat cggctctgcg ataaccatag actcatccca gggggccacc 10140 tttgatattg tgacattgca tctaccatcg ccaaaatctc taaacaaatc ccgagcactt 10200 gtggccatca ctcgggcaag acacgggttg ttcatttatg accctcataa tcagcttcag 10260 gagtttttca acctaacccc tgagcgtact gattgcaacc ttgtgttcag ccgtggggat 10320 gagctagtag ttctggatgc ggataatgca gtcacaactg tggcgaaggc cctagaaaca 10380 ggtccatctc gatttcgagt gtcagacccg aggtgcaagt ctctcttagc cgcttgttcg 10440 gccagtctgg aggggagctg tatgccacta ccgcaagtgg cacataactt ggggttttac 10500 ttttccccgg acagtccagc atttgcacct ctgccaagag agttggcgcc acattggcca 10560 gtagttaccc accagaataa tcgggcgtgg cctgatcgac ttgtcgctag tatgcgccca 10620 attgatgccc gctacagcaa gccaatggtc ggtgcagggt atgtggtcgg gccgtccacc 10680 tttcttggta ctcctggtgt ggtgtcatat tatctcacgc tgtacatcag gggtgagccc 10740 caggctttgc cagaaacact cgtttcaaca ggacgtatag ctacagattg tcgggagtat 10800 ctcgacgcgg ctgaggaaga ggcagcaaaa gaactccccc acgcatttat tggcgatgtc 10860 aaaggtacca cggtgggggg ttgtcatcac atcacatcaa agtacctacc taggtccctg 10920 cctaaggact ctattgccgt agttggagta agttcgcccg gcagggctgc taaagccatg 10980 tgcactctca ccgatgtgta tctccccgaa ctccggccct atctgcaacc tgagacggca 11040 tcaaaatgct ggaaactcaa attagacttc agggacgtcc gactaatggt ctggaaagga 11100 gccaccgcct atttccagtt ggaagggttt acatggtcgg cgctgcctga ctatgccagg 11160 tttattcagc tgcccaagga tgccgttgta tacattgatc cgtgtatagg accggcaaca 11220 gccaaccgca aggtcgtgcg aaccacagac tggcgggccg acctggcagt gacaccgtat 11280 gattacggtg cccagaacat tttgacaaca gcctggttcg aggacctcgg gccgcagtgg 11340 aagattttag ggttgcagcc ctttaggcga gcgtttggcc ttgaaaacac tgaggattgg 11400 gcaatccttg cacgtcgtat gaatgacggc aaggactaca ctgactataa ctggaactgt 11460 gttcgagaac gctcacacgc catctacgga cgtgctcgtg accatacata tcattttgcc 11520 cccggcacgg aactgcaggt ggagctaggt aaaccccggc tgccgcctgg gcaggtgccg 11580 tgaatttgga gtaatgcaat ggggtcactg tggagtaaga tcagccagct gttcgtggac 11640 gccttcactg agttccttgt tagtgtggtt gatattgtca tttttcttgc catactgttt 11700 gggttcaccg tcgcaggatg gttattggtc tttcttctca gagtggtttg ctccgcgctt 11760 ctccgttcgc gctctgccat tcactctccc gaactatcga aggtcctatg aaggcttgtt 11820 gcccaactgc agaccggacg tcccacaatt tgcagttaag cacccactgg gtatgttttg 11880 gcacatgcga gtttcccact tgattgatga gatggtctct cgccgcattt accagaccat 11940 ggaacattca ggacaagcgg catggaagca tgtggttggt gaggccactc tcacgaagct 12000 ttcagggctc gacatagtta cccatttcca acacctggcc gcagtggagg cggattcttg 12060 tcgctttctc agctcacgac tcgtgatgct aaagaatctt gccgttggca atgtgagcct 12120 acagtacaac accacgctga accgcgttga gctcattttc cccacgccag gcacgaggcc 12180 caagttgacc gacttcagac aatggctcat cagtgtgcac gcttccattt tttcctctgt 12240 ggcttcatct gttactttgt tcacagtgct ttggcttcga attccagctc tacgctatgt 12300 ttttggtttc cattggccca cggcaacaca tcattcgagc tgaccatcaa ctacaccgta 12360 tgcatgccct gtcctaccag tcaagcagct ctccaaaggc tcgagcccgg tcgtaacatg 12420 tggtgcaaaa tagggcatga taggtgtgag gagcgtgacc aagatgagtt gttaatgtcc 12480 atcccgtccg ggtacgacaa cctcaaactt gagggttatt atgcttggct ggcttttttg 12540 tctttttcct acgcggccca attccatcca gagttgttcg ggatcggaaa tgtgtcgcgc 12600 gtcttcgtgg acaagtggca ccagttcatt tgtgccgagc atgatggatc caattcaacc 12660 gtatctaccg gacacaacat ctccgcatta tatgcggcat attaccacca ccaaatagac 12720 gggggtaatt ggtttcattt ggaatggctg cggccattct tttcctcctg gctggtgctc 12780 aacatatcat ggtttctgag gcgttcgcct gtaagccctg tttctcgacg catctatcag 12840 atattaagac caacacgacc gcagctgccg gtttcatggt ccttcaggac atcaattgtt 12900 tccgacctca tgaggtctca gcaacgcaaa gggaaattcc cttcaggaag tcgtcccaat 12960 gccgtgaagc cgtcggcact ccccaatata tcacgataac agctaacgtg accgacgaat 13020 catatttgta caacgcggat ttgctgatgc tttctgcgtg ccttttctac gcttcagaaa 13080 tgagcgagaa aggcttcaaa gtcatctttg ggaatgtctc tggcgttgtt tctgcttgtg 13140 tcaatttcac ggattatgtg gcccatgtga cccaacatac ccagcagcat catctggtga 13200 ttgatcacat tcggctgctg catttcctga caccatctac aatgaggtgg gctacaacca 13260 ttgcctgttt gttcgccatt ctcttggcga tatgagatgt tcttacaaat tggggcgttc 13320 cttgattctg cactcttgct cctggtggtt ttttttgctg tgtaccggct tgtcttggtc 13380 ctttgccgat ggcaacggca acaactcgac ataccaatac atatataatt tgacgatatg 13440 cgagttaaat gggaccaatt ggctttccgg ccattttgat tgggcagttg agacctttgt 13500 gctttacccg gtcgtcactc atatcctctc actgggtttt ctcacgacaa gtcatttttt 13560 tgacgcgctc ggtctcggcg ctgtgtccac cgcaggattt attgacgggc ggtatgtgct 13620 cagcagcatc tacggcgctt gtgctttcgc agcgttcgta tgttttgtca tccgtgctgc 13680 taaaaattgc atggcctgcc gttacgcccg tacccggttt accaacttta ttgtggacga 13740 ccggggagga gttcatcggt ggaagtctcc aatagtggta gaaaaattgg gcaaagccga 13800 catcgacggc agccttgtca ccatcaaaca tgtcgtcctc gaaggggtta aagctcaacc 13860 cttgacaagg acttcggctg agcaatggga ggcctagatg atttttgcaa tgatcccacc 13920 gccgcacaaa agctcgtgct agcctttagc atcacataca cacctataat gatatacgcc 13980 cttaaggtgt cacgcggccg actcctgggg ctattgcaca tcctaatatt tctgaactgt 14040 tccttcacat tcggatacat gacatatgtg cattttcaat ccgccaaccg tgtcgcactt 14100 accctggggg ctgttgtcgc ccttctgtgg ggcgtttaca gcctcacaga gtcatggaag 14160 tttatcactt ccagatgcag attgtgttgc cttggccggc gatacattct ggcccctgcc 14220 catcacgtag aaagtgctgc aggtctccat tcaatctcag cgtctggtaa ccgagcatac 14280 gctgtgagaa agcccggatt aacatcagtg aacggcactc tagtaccagg acttcggagc 14340 ctcgtgctgg gcggcaaacg agctgttaaa cgaggagtgg ttaacctcgt caaatatggc 14400 cggtaaaaac cagagccaga agaaaaagaa aagtacagct ccaatgggga atggccagcc 14460 agtcaatcaa ctgtgccagt tgctgggtgc aatgataaag tcccagcgcc agcagcctag 14520 aggaggacag gccaaaaaga aaaagcctga gaagccacat ttccccctgg ctgcagaaga 14580 tgacatccgg catcacctta cccagactga acgttctctc tgcttgcaat cgatccagac 14640 ggctttcaat caaggcgcgg gaactgcgtc gctttcatcc agcgggaagg tcagttttca 14700 ggttgagttc atgctgccgg ttggtcatac agtgcgcctg attcgcgtga cttctacatc 14760 cgccagtcag ggtgcaagtt aatttgacag tcaggtgaat ggtcgcgatt ggcgtgtgac 14820 ctctgagtca cctattcaat tagggcgatc acatgggggt catacttaat caggcaggaa 14880 ccatgtgacc gaaatt 14896 2 2402 PRT Porcine reproductive and respiratory syndrome virus 2 Leu Leu Trp Gly Gly Thr Pro Glu Asp Phe Arg Arg Gly Pro Ala Leu 1 5 10 15 Leu Asp Val His Pro Leu Thr Met Cys Gly Ser Val Ser Arg Cys Met 20 25 30 Cys Thr Pro Ala Val Arg Val Phe Trp Asn Ala Gly Gln Val Phe Cys 35 40 45 Thr Arg Cys Val Ser Ala Arg Ala Leu Leu Ser Pro Glu Leu Gln Asp 50 55 60 Thr Asp Leu Gly Ala Val Gly Leu Phe Tyr Arg Pro Arg Asp Lys Leu 65 70 75 80 His Trp Lys Val Pro Ile Gly Ile Pro Gln Ala Glu Cys Thr Pro Ser 85 90 95 Gly Cys Cys Trp Leu Ser Ala Val Phe Pro Leu Ala Arg Met Thr Ser 100 105 110 Gly Asn His Asn Phe Leu Gln Arg Leu Val Lys Val Ala Asp Val Leu 115 120 125 Tyr Arg Asp Gly Cys Leu Ala Pro Arg His Leu Arg Glu Leu Gln Val 130 135 140 Tyr Glu Arg Gly Cys Asn Trp Tyr Pro Ile Thr Gly Pro Val Pro Gly 145 150 155 160 Met Gly Leu Phe Ala Asn Ser Met His Val Ser Asp Gln Pro Phe Pro 165 170 175 Gly Ala Thr His Val Leu Thr Asn Ser Pro Leu Pro Gln Gln Ala Cys 180 185 190 Arg Gln Pro Phe Cys Pro Phe Glu Glu Ala His Ser Gly Val Tyr Arg 195 200 205 Trp Lys Lys Phe Val Ile Phe Ser Asp Ser Pro Leu Asn Gly Gln Ser 210 215 220 Arg Ile Met Trp Thr Pro Lys Ser Asp Asp Ser Ala Ala Leu Glu Glu 225 230 235 240 Leu Pro Pro Glu Leu Glu Arg Gln Val Glu Ile Leu Ile Arg Ser Phe 245 250 255 Pro Ala His His Pro Val Asn Leu Ala Asp Trp Glu Leu Thr Gly Ser 260 265 270 Pro Glu Asn Gly Phe Ser Phe Asn Thr Ser His Ser Cys Gly His Leu 275 280 285 Val Arg Asn Ser Asn Val Phe Asp Gly Lys Cys Trp Leu Thr Cys Phe 290 295 300 Leu Gly Gln Ser Val Glu Val Arg Cys His Glu Glu His Leu Ala Asn 305 310 315 320 Ala Phe Gly Tyr Gln Thr Lys Trp Gly Val His Gly Lys Tyr Leu Gln 325 330 335 Arg Arg Leu Gln Val Arg Gly Ile Arg Ala Val Val Asp Pro Asp Gly 340 345 350 Pro Ile His Val Glu Ala Leu Ser Cys Ser Gln Ser Trp Ile Arg His 355 360 365 Leu Thr Leu Asn Asp Asp Val Thr Pro Gly Phe Val Arg Leu Thr Ser 370 375 380 Ile Arg Ile Val Pro Asn Thr Glu Pro Thr Thr Ser Gln Ile Phe Arg 385 390 395 400 Phe Gly Ala His Lys Trp Tyr Gly Ala Ala Gly Lys Arg Ala Arg Ala 405 410 415 Lys Arg Thr Ala Lys Gly Gly Lys Asp Ser Val Pro Ala Leu Lys Val 420 425 430 Ala Leu Pro Val Pro Ala Cys Gly Ile Thr Thr Tyr Ser Pro Pro Thr 435 440 445 Asp Gly Ser Cys Gly Trp His Val Leu Ala Ala Ile Met Asn Arg Met 450 455 460 Met Asn Asp Asp Phe Thr Ser Pro Leu Thr Gln Tyr Asn Arg Pro Glu 465 470 475 480 Asp Asp Trp Ala Ser Asp Tyr Asp Leu Ala Gln Ala Ile Gln Cys Leu 485 490 495 Gln Leu Pro Ala Thr Val Val Arg Asn Arg Ala Cys Pro Asn Ala Lys 500 505 510 Tyr Leu Ile Lys Leu Asn Gly Val His Trp Glu Val Glu Val Arg Ser 515 520 525 Gly Met Ala Pro Arg Ser Leu Ser Arg Glu Cys Val Val Gly Val Cys 530 535 540 Ser Glu Gly Cys Val Ala Pro Pro Tyr Pro Ala Asp Gly Leu Pro Lys 545 550 555 560 Arg Ala Leu Glu Ala Leu Ala Ser Ala Tyr Arg Leu Pro Ser Asp Cys 565 570 575 Val Cys Ser Gly Ile Ala Asp Phe Leu Ala Asn Pro Pro Pro Gln Glu 580 585 590 Phe Trp Thr Leu Asp Lys Met Leu Thr Ser Pro Ser Pro Glu Arg Ser 595 600 605 Gly Phe Ser Ser Leu Tyr Asn Leu Leu Leu Glu Val Val Pro Gln Lys 610 615 620 Cys Gly Val Thr Glu Gly Ala Phe Thr Tyr Ala Val Glu Arg Met Leu 625 630 635 640 Met Asp Cys Pro Ser Ser Glu Gln Ala Met Ala Leu Leu Ala Lys Ile 645 650 655 Lys Val Pro Ser Ser Lys Ala Pro Ser Val Ser Leu Asp Glu Cys Phe 660 665 670 Pro Ala Asp Val Pro Ala Asp Phe Glu Pro Thr Ser Gln Lys Arg Pro 675 680 685 Gln Ser Ser Gly Ala Ala Val Ala Leu Cys Ser Ser Asp Ala Glu Gly 690 695 700 Phe Glu Glu Ala Ala Pro Glu Gly Val Gln Glu Arg Gly His Lys Ala 705 710 715 720 Val His Ser Ala Leu Phe Ala Lys Gly Pro Asn Asn Glu Gln Val Gln 725 730 735 Val Val Ala Gly Glu Gln Gln Lys Leu Gly Gly Cys Gly Leu Ala Ile 740 745 750 Gly Asn Ala Gln Ser Pro Leu Asn Ser Met Lys Glu Asn Met Arg Ser 755 760 765 Ser Arg Glu Asp Glu Pro Leu Asp Leu Ser Gln Pro Ala Pro Val Ala 770 775 780 Ala Thr Thr Leu Glu Arg Glu Gln Thr Pro Asp Asn Pro Gly Ser Asp 785 790 795 800 Ala Gly Ala Leu Pro Ala Thr Val Arg Glu Ser Val Pro Thr Gly Pro 805 810 815 Met Leu Arg His Val Glu His Cys Gly Thr Glu Ser Gly Asp Ser Ser 820 825 830 Ser Pro Leu Asp Leu Ser Tyr Ala Gln Thr Leu Asp Gln Pro Leu Asp 835 840 845 Leu Ser Leu Ala Val Trp Pro Val Lys Ala Thr Ala Ser Asp Pro Gly 850 855 860 Trp Val His Gly Arg Arg Glu Pro Val Phe Val Lys Pro Arg Lys Ala 865 870 875 880 Phe Ser Asp Ser Asp Ser Ala Phe Gln Phe Gly Lys Leu Ser Glu Ser 885 890 895 Gly Ser Val Ile Glu Phe Asp Arg Thr Lys Asp Ala Pro Val Val Asp 900 905 910 Ala Pro Val Gly Ser Thr Thr Ser Asn Glu Ala Leu Ser Ile Ala Asp 915 920 925 Pro Phe Glu Phe Ala Glu Leu Lys Arg Pro Arg Phe Ser Ala Gln Ala 930 935 940 Leu Ile Asp Arg Gly Gly Pro Leu Ala Asp Val His Ala Lys Ile Lys 945 950 955 960 Asn Arg Val Tyr Glu Arg Cys Leu Gln Ala Cys Glu Pro Gly Ser Arg 965 970 975 Ala Thr Pro Ala Thr Lys Glu Trp Leu Asp Lys Met Trp Asp Arg Val 980 985 990 Asp Met Lys Thr Trp Cys Cys Thr Ser Gln Phe Gln Ala Gly Arg Ile 995 1000 1005 Leu Ala Ser Leu Lys Phe Leu Pro Asp Met Ile Gln Asp Thr Pro Pro 1010 1015 1020 Pro Val Pro Arg Lys Asn Arg Ala Ser Asp Asn Ala Asp Leu Lys Gln 1025 1030 1035 1040 Leu Val Ala Gln Trp Asp Arg Lys Leu Ser Met Thr Pro Pro Gln Lys 1045 1050 1055 Pro Val Glu Pro Val Leu Asp Gln Thr Val Ser Pro Pro Thr Asp Thr 1060 1065 1070 Gln Gln Glu Asp Val Thr Pro Ser Asp Gly Pro Pro His Ala Pro Asp 1075 1080 1085 Phe Pro Ser Arg Val Ser Thr Gly Gly Ser Trp Lys Asp Leu Met Cys 1090 1095 1100 Ser Gly Thr Arg Leu Ala Gly Ser Ile Ser Gln Arg Leu Met Thr Trp 1105 1110 1115 1120 Val Phe Glu Val Phe Ser His Leu Pro Ala Phe Met Leu Thr Leu Phe 1125 1130 1135 Ser Pro Arg Gly Ser Met Ala Pro Gly Asp Trp Leu Phe Ala Gly Val 1140 1145 1150 Val Leu Leu Ala Leu Leu Leu Cys His Ser Tyr Pro Ile Leu Gly Cys 1155 1160 1165 Leu Pro Leu Leu Gly Val Phe Ser Gly Ser Leu Arg Arg Val Arg Leu 1170 1175 1180 Gly Val Phe Gly Ser Trp Met Ala Phe Ala Val Phe Leu Phe Ser Thr 1185 1190 1195 1200 Pro Ser Asn Pro Val Gly Ser Ser Cys Asp His Asp Ser Pro Glu Cys 1205 1210 1215 His Ala Glu Leu Leu Ala Leu Glu Gln Arg Gln Leu Trp Glu Pro Val 1220 1225 1230 Arg Gly Leu Val Val Gly Pro Ser Gly Leu Leu Cys Val Ile Leu Gly 1235 1240 1245 Lys Leu Leu Gly Gly Ser Arg Tyr Leu Trp His Ile Leu Leu Arg Leu 1250 1255 1260 Cys Met Leu Thr Asp Leu Ala Leu Ser Leu Val Tyr Val Val Ser Gln 1265 1270 1275 1280 Gly Arg Cys His Lys Cys Trp Gly Lys Cys Ile Arg Thr Ala Pro Thr 1285 1290 1295 Glu Val Ala Leu Asn Val Phe Pro Phe Thr Arg Ala Thr Arg Ser Ser 1300 1305 1310 Leu Val Ser Leu Cys Asp Arg Phe Gln Thr Pro Lys Gly Val Asp Pro 1315 1320 1325 Val His Leu Ala Thr Gly Trp Arg Gly Cys Trp Arg Gly Gly Ser Pro 1330 1335 1340 Val His Gln Pro His Gln Lys Pro Ile Ala Tyr Ala Asn Leu Asp Glu 1345 1350 1355 1360 Lys Lys Ile Ser Ala Gln Thr Val Val Ala Val Pro Tyr Asp Pro Ser 1365 1370 1375 Gln Ala Ile Lys Cys Leu Lys Val Leu Gln Ala Gly Gly Ala Ile Val 1380 1385 1390 Asp Gln Pro Thr Pro Glu Val Val Arg Val Ser Glu Ile Pro Phe Ser 1395 1400 1405 Ala Pro Phe Phe Pro Lys Val Pro Val Asn Pro Asp Cys Arg Val Val 1410 1415 1420 Val Asp Ser Asp Thr Phe Val Ala Ala Val Arg Cys Gly Tyr Ser Thr 1425 1430 1435 1440 Ala Gln Leu Val Leu Gly Gln Gly Asn Phe Ala Lys Leu Asn Gln Thr 1445 1450 1455 Pro Pro Arg Asn Ser Thr Ser Thr Lys Thr Thr Gly Gly Ala Ser Tyr 1460 1465 1470 Thr Leu Ala Val Ala Gln Val Thr Val Trp Thr Leu Phe His Phe Ile 1475 1480 1485 Leu Gly Leu Trp Phe Thr Ser Pro Gln Val Cys Gly Arg Gly Thr Ala 1490 1495 1500 Asp Pro Trp Cys Ser Asn Pro Phe Ser Tyr Pro Thr Tyr Gly Pro Gly 1505 1510 1515 1520 Val Val Cys Ser Ser Arg Leu Cys Val Ser Ala Asp Gly Val Thr Leu 1525 1530 1535 Pro Leu Phe Ser Ala Val Ala Gln Leu Ser Gly Arg Glu Val Gly Ile 1540 1545 1550 Phe Ile Leu Val Leu Val Ser Leu Ile Ala Leu Ala His Arg Met Ala 1555 1560 1565 Leu Lys Ala Asp Met Leu Val Val Phe Leu Ala Phe Cys Ala Tyr Ala 1570 1575 1580 Trp Pro Met Ser Ser Trp Leu Ile Cys Phe Phe Pro Leu Leu Leu Lys 1585 1590 1595 1600 Trp Val Thr Leu His Pro Leu Thr Met Leu Trp Val His Ser Phe Leu 1605 1610 1615 Val Phe Cys Leu Pro Ala Ala Gly Ile Leu Ser Leu Gly Thr Thr Gly 1620 1625 1630 Leu Leu Trp Ala Ile Gly Arg Phe Thr Gln Val Ala Gly Ile Ile Thr 1635 1640 1645 Pro Tyr Asp Ile His Gln Tyr Thr Ser Gly Pro Arg Gly Ala Ala Ala 1650 1655 1660 Val Ala Thr Ala Pro Glu Gly Thr Tyr Met Ala Ala Val Arg Arg Ala 1665 1670 1675 1680 Ala Leu Thr Gly Arg Thr Leu Ile Phe Thr Pro Ser Ala Val Gly Ser 1685 1690 1695 Leu Leu Glu Gly Ala Phe Arg Thr Gln Lys Pro Cys Leu Asn Thr Val 1700 1705 1710 Asn Val Val Gly Ser Ser Leu Gly Ser Gly Gly Val Phe Thr Ile Asn 1715 1720 1725 Gly Arg Arg Thr Val Val Thr Ala Ala His Val Leu Asn Gly Asp Thr 1730 1735 1740 Ala Arg Val Thr Gly Asp Ser Tyr Asn Arg Met His Thr Phe Lys Thr 1745 1750 1755 1760 Asn Gly Asp Tyr Ala Trp Ser His Ala Asp Asp Trp Gln Gly Val Ala 1765 1770 1775 Pro Val Val Lys Val Ala Lys Gly Tyr Arg Gly Arg Ala Tyr Trp Gln 1780 1785 1790 Thr Ser Thr Gly Val Glu Pro Gly Ile Ile Gly Glu Gly Phe Ala Phe 1795 1800 1805 Cys Phe Thr Asn Cys Gly Asp Ser Gly Ser Pro Val Ile Ser Glu Ser 1810 1815 1820 Gly Asp Leu Ile Gly Ile His Thr Gly Ser Asn Lys Leu Gly Ser Gly 1825 1830 1835 1840 Leu Val Thr Thr Pro Glu Gly Glu Thr Cys Ala Ile Lys Glu Thr Lys 1845 1850 1855 Leu Ser Asp Leu Ser Arg His Phe Ala Gly Pro Ser Val Pro Leu Gly 1860 1865 1870 Asp Ile Lys Leu Ser Pro Ala Ile Ile Pro Asp Val Thr Ser Ile Pro 1875 1880 1885 Ser Asp Leu Ala Ser Leu Leu Ala Ser Val Pro Val Leu Glu Gly Gly 1890 1895 1900 Leu Ser Thr Val Gln Leu Leu Cys Val Phe Phe Leu Leu Trp Arg Met 1905 1910 1915 1920 Met Gly His Ala Trp Thr Pro Ile Val Ala Val Gly Phe Phe Leu Leu 1925 1930 1935 Asn Glu Ile Leu Pro Ala Val Leu Val Arg Ala Val Phe Ser Phe Ala 1940 1945 1950 Leu Phe Val Leu Ala Trp Val Thr Pro Trp Ser Ala Gln Val Leu Met 1955 1960 1965 Ile Arg Leu Leu Thr Ala Ser Leu Asn Arg Asn Lys Phe Ser Leu Ala 1970 1975 1980 Phe Tyr Ala Leu Gly Gly Val Ile Gly Leu Ala Ala Glu Ile Gly Thr 1985 1990 1995 2000 Phe Ala Gly Arg Leu Pro Glu Leu Ser Gln Ala Leu Ser Thr Tyr Cys 2005 2010 2015 Phe Leu Pro Arg Val Leu Ala Met Ala Ser Cys Val Pro Ile Ile Ile 2020 2025 2030 Ile Gly Gly Leu His Thr Leu Gly Val Ile Leu Trp Leu Phe Lys Tyr 2035 2040 2045 Arg Cys Leu His Asn Met Leu Val Gly Asp Gly Ser Phe Ser Ser Ala 2050 2055 2060 Phe Phe Leu Arg Tyr Phe Ala Glu Gly Asn Leu Arg Lys Gly Val Ser 2065 2070 2075 2080 Gln Ser Cys Gly Met Asn Asn Glu Ser Leu Thr Ala Ala Leu Ala Cys 2085 2090 2095 Lys Leu Ser Gln Ala Asp Leu Asp Phe Leu Ser Ser Leu Thr Asn Phe 2100 2105 2110 Lys Cys Phe Val Ser Ala Ser Asn Met Lys Asn Ala Ala Gly Gln Tyr 2115 2120 2125 Ile Glu Ala Ala Tyr Ala Arg Ala Leu Arg Gln Glu Leu Ala Ser Leu 2130 2135 2140 Val Gln Val Asp Lys Met Lys Gly Val Leu Ser Lys Leu Glu Ala Phe 2145 2150 2155 2160 Ala Glu Thr Ala Thr Pro Ser Leu Asp Thr Gly Asp Val Val Val Leu 2165 2170 2175 Leu Gly Gln His Pro His Gly Ser Ile Leu Asp Ile Asn Val Gly Thr 2180 2185 2190 Glu Arg Lys Thr Val Ser Val Gln Glu Thr Arg Ser Leu Gly Gly Ser 2195 2200 2205 Lys Phe Ser Val Cys Thr Val Val Ser Asn Thr Pro Val Asp Ala Leu 2210 2215 2220 Thr Gly Ile Pro Leu Gln Thr Pro Thr Pro Leu Phe Glu Asn Gly Pro 2225 2230 2235 2240 Arg His Arg Ser Glu Glu Asp Asp Leu Lys Val Glu Arg Met Lys Lys 2245 2250 2255 His Cys Val Ser Leu Gly Phe His Asn Ile Asn Gly Lys Val Tyr Cys 2260 2265 2270 Lys Ile Trp Asp Lys Ser Thr Gly Asp Thr Phe Tyr Thr Asp Asp Ser 2275 2280 2285 Arg Tyr Thr Gln Asp Tyr Ala Phe Gln Asp Arg Ser Ala Asp Tyr Arg 2290 2295 2300 Asp Arg Asp Tyr Glu Gly Val Gln Thr Ala Pro Gln Gln Gly Phe Asp 2305 2310 2315 2320 Pro Lys Ser Glu Thr Pro Val Gly Thr Val Val Ile Gly Gly Ile Thr 2325 2330 2335 Tyr Asn Arg Tyr Leu Ile Lys Gly Lys Glu Ile Leu Val Pro Lys Pro 2340 2345 2350 Asp Asn Cys Leu Glu Ala Ala Lys Leu Ser Leu Glu Gln Ala Leu Ala 2355 2360 2365 Gly Met Gly Gln Thr Cys Asp Leu Thr Ala Ala Glu Val Glu Lys Leu 2370 2375 2380 Lys Arg Ile Ile Ser Gln Leu Gln Gly Leu Thr Thr Glu Gln Ala Leu 2385 2390 2395 2400 Asn Cys 3 1458 PRT Porcine reproductive and respiratory syndrome virus 3 Leu Ala Ala Ser Gly Leu Thr Arg Cys Gly Arg Gly Gly Leu Val Val 1 5 10 15 Thr Glu Thr Ala Val Lys Ile Val Lys Tyr His Ser Arg Thr Phe Thr 20 25 30 Phe Gly Pro Leu Asp Leu Lys Val Thr Ser Glu Ala Glu Val Lys Lys 35 40 45 Ser Thr Glu Gln Gly His Ala Val Val Ala Asn Leu Cys Ser Gly Val 50 55 60 Ile Leu Met Arg Pro His Pro Pro Ser Leu Val Asp Val Leu Leu Lys 65 70 75 80 Pro Gly Leu Asp Thr Lys Pro Gly Ile Gln Pro Gly His Gly Ala Gly 85 90 95 Asn Met Gly Val Asp Gly Ser Met Trp Asp Phe Glu Thr Ala Pro Thr 100 105 110 Lys Ala Glu Leu Glu Leu Ser Lys Gln Ile Ile Gln Ala Cys Glu Val 115 120 125 Arg Arg Gly Asp Ala Pro Asn Leu Gln Leu Pro Tyr Lys Leu Tyr Pro 130 135 140 Val Arg Gly Asp Pro Ala Arg His Gly Gly Arg Leu Ile Asn Thr Arg 145 150 155 160 Phe Gly Asp Leu Ser Tyr Lys Thr Pro Gln Asp Thr Lys Ser Ala Ile 165 170 175 His Ala Ala Cys Cys Leu His Pro Asn Gly Ala Pro Val Ser Asp Gly 180 185 190 Lys Ser Thr Leu Gly Thr Thr Leu Gln His Gly Phe Glu Leu Tyr Val 195 200 205 Pro Thr Val Pro Tyr Ser Val Met Glu Tyr Leu Asp Ser Arg Pro Asp 210 215 220 Thr Pro Phe Met Cys Thr Lys His Gly Thr Ser Lys Ala Ala Ala Glu 225 230 235 240 Asp Leu Gln Lys Tyr Asp Leu Ser Thr Gln Gly Phe Val Leu Pro Gly 245 250 255 Val Leu Arg Leu Val Arg Arg Phe Ile Phe Gly His Ile Gly Lys Ala 260 265 270 Pro Pro Leu Phe Leu Pro Ser Thr Tyr Pro Ala Lys Asn Ser Met Ala 275 280 285 Gly Ile Asn Gly Gln Arg Phe Pro Thr Lys Asp Val Gln Ser Ile Pro 290 295 300 Glu Ile Asp Glu Met Cys Ala Arg Ala Val Lys Glu Asn Trp Gln Thr 305 310 315 320 Val Thr Pro Cys Thr Leu Lys Lys Gln Tyr Cys Ser Lys Pro Lys Thr 325 330 335 Arg Thr Ile Leu Gly Thr Asn Asn Phe Ile Ala Leu Ala His Arg Ser 340 345 350 Ala Leu Ser Gly Val Thr Gln Ala Phe Met Lys Lys Ala Trp Lys Ser 355 360 365 Pro Ile Ala Leu Gly Lys Asn Lys Phe Lys Glu Leu His Cys Thr Val 370 375 380 Ala Gly Arg Cys Leu Glu Ala Asp Leu Ala Ser Cys Asp Arg Ser Thr 385 390 395 400 Pro Ala Ile Val Arg Trp Phe Val Ala Asn Leu Leu Tyr Glu Leu Ala 405 410 415 Gly Cys Glu Glu Tyr Leu Pro Ser Tyr Val Leu Asn Cys Cys His Asp 420 425 430 Leu Val Ala Thr Gln Asp Gly Ala Phe Thr Lys Arg Gly Gly Leu Ser 435 440 445 Ser Gly Asp Pro Val Thr Ser Val Ser Asn Thr Val Tyr Ser Leu Val 450 455 460 Ile Tyr Ala Gln His Met Val Leu Ser Ala Leu Lys Met Gly His Glu 465 470 475 480 Ile Gly Leu Lys Phe Leu Glu Glu Gln Leu Lys Phe Glu Asp Leu Leu 485 490 495 Glu Ile Gln Pro Met Leu Val Tyr Ser Asp Asp Leu Val Leu Tyr Ala 500 505 510 Glu Arg Pro Thr Phe Pro Asn Tyr His Trp Trp Val Glu His Leu Asp 515 520 525 Leu Met Leu Gly Phe Arg Thr Asp Pro Lys Lys Thr Val Ile Thr Asp 530 535 540 Lys Pro Ser Phe Leu Gly Cys Arg Ile Glu Ala Gly Arg Gln Leu Val 545 550 555 560 Pro Asn Arg Asp Arg Ile Leu Ala Ala Leu Ala Tyr His Met Lys Ala 565 570 575 Gln Asn Ala Ser Glu Tyr Tyr Ala Ser Ala Ala Ala Ile Leu Met Asp 580 585 590 Ser Cys Ala Cys Ile Asp His Asp Pro Glu Trp Tyr Glu Asp Leu Ile 595 600 605 Cys Gly Ile Ala Gln Cys Ala Arg Gln Asp Gly Tyr Ser Phe Pro Gly 610 615 620 Pro Ala Phe Phe Met Ser Met Trp Glu Arg Leu Arg Ser His Asn Glu 625 630 635 640 Gly Lys Lys Phe Arg His Cys Gly Ile Cys Asp Ala Lys Ala Asp Tyr 645 650 655 Ala Ser Ala Cys Gly Leu Asp Leu Cys Leu Phe His Ser His Phe His 660 665 670 Gln His Cys Pro Val Thr Leu Ser Cys Gly His His Ala Gly Ser Arg 675 680 685 Glu Cys Ser Gln Cys Gln Ser Pro Val Gly Ala Gly Arg Ser Pro Leu 690 695 700 Asp Ala Val Leu Lys Gln Ile Pro Tyr Lys Pro Pro Arg Thr Val Ile 705 710 715 720 Met Lys Val Gly Asn Lys Thr Thr Ala Leu Asp Pro Gly Arg Tyr Gln 725 730 735 Ser Arg Arg Gly Leu Val Ala Val Lys Arg Gly Ile Ala Gly Asn Glu 740 745 750 Val Asp Leu Ser Asp Gly Asp Tyr Gln Val Val Pro Leu Leu Pro Thr 755 760 765 Cys Lys Asp Ile Asn Met Val Lys Val Ala Cys Asn Val Leu Leu Ser 770 775 780 Lys Phe Ile Val Gly Pro Pro Gly Ser Gly Lys Thr Thr Trp Leu Leu 785 790 795 800 Gly Gln Val Gln Asp Asp Asp Val Ile Tyr Thr Pro Thr His Gln Thr 805 810 815 Met Phe Asp Ile Val Ser Ala Leu Lys Val Cys Arg Tyr Thr Ile Pro 820 825 830 Gly Ala Ser Gly Leu Pro Phe Pro Pro Pro Ala Arg Ser Gly Pro Trp 835 840 845 Val Arg Leu Ile Ala Ser Gly His Val Pro Gly Arg Val Ser Tyr Leu 850 855 860 Asp Glu Ala Gly Tyr Cys Asn His Leu Asp Ile Leu Arg Leu Leu Ser 865 870 875 880 Lys Thr Pro Leu Val Cys Leu Gly Asp Leu Gln Gln Leu His Pro Val 885 890 895 Gly Phe Asp Ser Tyr Cys Tyr Val Phe Asp Gln Met Pro Gln Lys Gln 900 905 910 Leu Thr Thr Ile Tyr Arg Phe Gly Pro Asn Ile Cys Ala Ala Ile Gln 915 920 925 Pro Cys Tyr Arg Glu Lys Leu Glu Ser Lys Ala Arg Asn Thr Arg Val 930 935 940 Val Phe Thr Thr Arg Pro Val Ala Phe Gly Gln Val Leu Thr Pro Tyr 945 950 955 960 His Lys Asp Arg Ile Gly Ser Ala Ile Thr Ile Asp Ser Ser Gln Gly 965 970 975 Ala Thr Phe Asp Ile Val Thr Leu His Leu Pro Ser Pro Lys Ser Leu 980 985 990 Asn Lys Ser Arg Ala Leu Val Ala Ile Thr Arg Ala Arg His Gly Leu 995 1000 1005 Phe Ile Tyr Asp Pro His Asn Gln Leu Gln Glu Phe Phe Asn Leu Thr 1010 1015 1020 Pro Glu Arg Thr Asp Cys Asn Leu Val Phe Ser Arg Gly Asp Glu Leu 1025 1030 1035 1040 Val Val Leu Asp Ala Asp Asn Ala Val Thr Thr Val Ala Lys Ala Leu 1045 1050 1055 Glu Thr Gly Pro Ser Arg Phe Arg Val Ser Asp Pro Arg Cys Lys Ser 1060 1065 1070 Leu Leu Ala Ala Cys Ser Ala Ser Leu Glu Gly Ser Cys Met Pro Leu 1075 1080 1085 Pro Gln Val Ala His Asn Leu Gly Phe Tyr Phe Ser Pro Asp Ser Pro 1090 1095 1100 Ala Phe Ala Pro Leu Pro Arg Glu Leu Ala Pro His Trp Pro Val Val 1105 1110 1115 1120 Thr His Gln Asn Asn Arg Ala Trp Pro Asp Arg Leu Val Ala Ser Met 1125 1130 1135 Arg Pro Ile Asp Ala Arg Tyr Ser Lys Pro Met Val Gly Ala Gly Tyr 1140 1145 1150 Val Val Gly Pro Ser Thr Phe Leu Gly Thr Pro Gly Val Val Ser Tyr 1155 1160 1165 Tyr Leu Thr Leu Tyr Ile Arg Gly Glu Pro Gln Ala Leu Pro Glu Thr 1170 1175 1180 Leu Val Ser Thr Gly Arg Ile Ala Thr Asp Cys Arg Glu Tyr Leu Asp 1185 1190 1195 1200 Ala Ala Glu Glu Glu Ala Ala Lys Glu Leu Pro His Ala Phe Ile Gly 1205 1210 1215 Asp Val Lys Gly Thr Thr Val Gly Gly Cys His His Ile Thr Ser Lys 1220 1225 1230 Tyr Leu Pro Arg Ser Leu Pro Lys Asp Ser Ile Ala Val Val Gly Val 1235 1240 1245 Ser Ser Pro Gly Arg Ala Ala Lys Ala Met Cys Thr Leu Thr Asp Val 1250 1255 1260 Tyr Leu Pro Glu Leu Arg Pro Tyr Leu Gln Pro Glu Thr Ala Ser Lys 1265 1270 1275 1280 Cys Trp Lys Leu Lys Leu Asp Phe Arg Asp Val Arg Leu Met Val Trp 1285 1290 1295 Lys Gly Ala Thr Ala Tyr Phe Gln Leu Glu Gly Phe Thr Trp Ser Ala 1300 1305 1310 Leu Pro Asp Tyr Ala Arg Phe Ile Gln Leu Pro Lys Asp Ala Val Val 1315 1320 1325 Tyr Ile Asp Pro Cys Ile Gly Pro Ala Thr Ala Asn Arg Lys Val Val 1330 1335 1340 Arg Thr Thr Asp Trp Arg Ala Asp Leu Ala Val Thr Pro Tyr Asp Tyr 1345 1350 1355 1360 Gly Ala Gln Asn Ile Leu Thr Thr Ala Trp Phe Glu Asp Leu Gly Pro 1365 1370 1375 Gln Trp Lys Ile Leu Gly Leu Gln Pro Phe Arg Arg Ala Phe Gly Leu 1380 1385 1390 Glu Asn Thr Glu Asp Trp Ala Ile Leu Ala Arg Arg Met Asn Asp Gly 1395 1400 1405 Lys Asp Tyr Thr Asp Tyr Asn Trp Asn Cys Val Arg Glu Arg Ser His 1410 1415 1420 Ala Ile Tyr Gly Arg Ala Arg Asp His Thr Tyr His Phe Ala Pro Gly 1425 1430 1435 1440 Thr Glu Leu Gln Val Glu Leu Gly Lys Pro Arg Leu Pro Pro Gly Gln 1445 1450 1455 Val Pro 4 249 PRT Porcine reproductive and respiratory syndrome virus 4 Met Gln Trp Gly His Cys Gly Val Arg Ser Ala Ser Cys Ser Trp Thr 1 5 10 15 Pro Ser Leu Ser Ser Leu Leu Val Trp Leu Ile Leu Ser Phe Phe Leu 20 25 30 Pro Tyr Cys Leu Gly Ser Pro Ser Gln Asp Gly Tyr Trp Ser Phe Phe 35 40 45 Ser Glu Trp Phe Ala Pro Arg Phe Ser Val Arg Ala Leu Pro Phe Thr 50 55 60 Leu Pro Asn Tyr Arg Arg Ser Tyr Glu Gly Leu Leu Pro Asn Cys Arg 65 70 75 80 Pro Asp Val Pro Gln Phe Ala Val Lys His Pro Leu Gly Met Phe Trp 85 90 95 His Met Arg Val Ser His Leu Ile Asp Glu Met Val Ser Arg Arg Ile 100 105 110 Tyr Gln Thr Met Glu His Ser Gly Gln Ala Ala Trp Lys His Val Val 115 120 125 Gly Glu Ala Thr Leu Thr Lys Leu Ser Gly Leu Asp Ile Val Thr His 130 135 140 Phe Gln His Leu Ala Ala Val Glu Ala Asp Ser Cys Arg Phe Leu Ser 145 150 155 160 Ser Arg Leu Val Met Leu Lys Asn Leu Ala Val Gly Asn Val Ser Leu 165 170 175 Gln Tyr Asn Thr Thr Leu Asn Arg Val Glu Leu Ile Phe Pro Thr Pro 180 185 190 Gly Thr Arg Pro Lys Leu Thr Asp Phe Arg Gln Trp Leu Ile Ser Val 195 200 205 His Ala Ser Ile Phe Ser Ser Val Ala Ser Ser Val Thr Leu Phe Thr 210 215 220 Val Leu Trp Leu Arg Ile Pro Ala Leu Arg Tyr Val Phe Gly Phe His 225 230 235 240 Trp Pro Thr Ala Thr His His Ser Ser 245 5 265 PRT Porcine reproductive and respiratory syndrome virus 5 Met Ala His Gln Cys Ala Arg Phe His Phe Phe Leu Cys Gly Phe Ile 1 5 10 15 Cys Tyr Phe Val His Ser Ala Leu Ala Ser Asn Ser Ser Ser Thr Leu 20 25 30 Cys Phe Trp Phe Pro Leu Ala His Gly Asn Thr Ser Phe Glu Leu Thr 35 40 45 Ile Asn Tyr Thr Val Cys Met Pro Cys Pro Thr Ser Gln Ala Ala Leu 50 55 60 Gln Arg Leu Glu Pro Gly Arg Asn Met Trp Cys Lys Ile Gly His Asp 65 70 75 80 Arg Cys Glu Glu Arg Asp Gln Asp Glu Leu Leu Met Ser Ile Pro Ser 85 90 95 Gly Tyr Asp Asn Leu Lys Leu Glu Gly Tyr Tyr Ala Trp Leu Ala Phe 100 105 110 Leu Ser Phe Ser Tyr Ala Ala Gln Phe His Pro Glu Leu Phe Gly Ile 115 120 125 Gly Asn Val Ser Arg Val Phe Val Asp Lys Trp His Gln Phe Ile Cys 130 135 140 Ala Glu His Asp Gly Ser Asn Ser Thr Val Ser Thr Gly His Asn Ile 145 150 155 160 Ser Ala Leu Tyr Ala Ala Tyr Tyr His His Gln Ile Asp Gly Gly Asn 165 170 175 Trp Phe His Leu Glu Trp Leu Arg Pro Phe Phe Ser Ser Trp Leu Val 180 185 190 Leu Asn Ile Ser Trp Phe Leu Arg Arg Ser Pro Val Ser Pro Val Ser 195 200 205 Arg Arg Ile Tyr Gln Ile Leu Arg Pro Thr Arg Pro Gln Leu Pro Val 210 215 220 Ser Trp Ser Phe Arg Thr Ser Ile Val Ser Asp Leu Met Arg Ser Gln 225 230 235 240 Gln Arg Lys Gly Lys Phe Pro Ser Gly Ser Arg Pro Asn Ala Val Lys 245 250 255 Pro Ser Ala Leu Pro Asn Ile Ser Arg 260 265 6 183 PRT Porcine reproductive and respiratory syndrome virus 6 Met Ala Ala Ala Ile Leu Phe Leu Leu Ala Gly Ala Gln His Ile Met 1 5 10 15 Val Ser Glu Ala Phe Ala Cys Lys Pro Cys Phe Ser Thr His Leu Ser 20 25 30 Asp Ile Lys Thr Asn Thr Thr Ala Ala Ala Gly Phe Met Val Leu Gln 35 40 45 Asp Ile Asn Cys Phe Arg Pro His Glu Val Ser Ala Thr Gln Arg Glu 50 55 60 Ile Pro Phe Arg Lys Ser Ser Gln Cys Arg Glu Ala Val Gly Thr Pro 65 70 75 80 Gln Tyr Ile Thr Ile Thr Ala Asn Val Thr Asp Glu Ser Tyr Leu Tyr 85 90 95 Asn Ala Asp Leu Leu Met Leu Ser Ala Cys Leu Phe Tyr Ala Ser Glu 100 105 110 Met Ser Glu Lys Gly Phe Lys Val Ile Phe Gly Asn Val Ser Gly Val 115 120 125 Val Ser Ala Cys Val Asn Phe Thr Asp Tyr Val Ala His Val Thr Gln 130 135 140 His Thr Gln Gln His His Leu Val Ile Asp His Ile Arg Leu Leu His 145 150 155 160 Phe Leu Thr Pro Ser Thr Met Arg Trp Ala Thr Thr Ile Ala Cys Leu 165 170 175 Phe Ala Ile Leu Leu Ala Ile 180 7 201 PRT Porcine reproductive and respiratory syndrome virus 7 Met Arg Cys Ser Tyr Lys Leu Gly Arg Ser Leu Ile Leu His Ser Cys 1 5 10 15 Ser Trp Trp Phe Phe Leu Leu Cys Thr Gly Leu Ser Trp Ser Phe Ala 20 25 30 Asp Gly Asn Gly Asn Asn Ser Thr Tyr Gln Tyr Ile Tyr Asn Leu Thr 35 40 45 Ile Cys Glu Leu Asn Gly Thr Asn Trp Leu Ser Gly His Phe Asp Trp 50 55 60 Ala Val Glu Thr Phe Val Leu Tyr Pro Val Val Thr His Ile Leu Ser 65 70 75 80 Leu Gly Phe Leu Thr Thr Ser His Phe Phe Asp Ala Leu Gly Leu Gly 85 90 95 Ala Val Ser Thr Ala Gly Phe Ile Asp Gly Arg Tyr Val Leu Ser Ser 100 105 110 Ile Tyr Gly Ala Cys Ala Phe Ala Ala Phe Val Cys Phe Val Ile Arg 115 120 125 Ala Ala Lys Asn Cys Met Ala Cys Arg Tyr Ala Arg Thr Arg Phe Thr 130 135 140 Asn Phe Ile Val Asp Asp Arg Gly Gly Val His Arg Trp Lys Ser Pro 145 150 155 160 Ile Val Val Glu Lys Leu Gly Lys Ala Asp Ile Asp Gly Ser Leu Val 165 170 175 Thr Ile Lys His Val Val Leu Glu Gly Val Lys Ala Gln Pro Leu Thr 180 185 190 Arg Thr Ser Ala Glu Gln Trp Glu Ala 195 200 8 108 PRT Porcine reproductive and respiratory syndrome virus 8 Met Gly Pro Ile Gly Phe Pro Ala Ile Leu Ile Gly Gln Leu Arg Pro 1 5 10 15 Leu Cys Phe Thr Arg Ser Ser Leu Ile Ser Ser His Trp Val Phe Ser 20 25 30 Arg Gln Val Ile Phe Leu Thr Arg Ser Val Ser Ala Leu Cys Pro Pro 35 40 45 Gln Asp Leu Leu Thr Gly Gly Met Cys Ser Ala Ala Ser Thr Ala Leu 50 55 60 Val Leu Ser Gln Arg Ser Tyr Val Leu Ser Ser Val Leu Leu Lys Ile 65 70 75 80 Ala Trp Pro Ala Val Thr Pro Val Pro Gly Leu Pro Thr Leu Leu Trp 85 90 95 Thr Thr Gly Glu Glu Phe Ile Gly Gly Ser Leu Gln 100 105 9 173 PRT Porcine reproductive and respiratory syndrome virus 9 Met Gly Gly Leu Asp Asp Phe Cys Asn Asp Pro Thr Ala Ala Gln Lys 1 5 10 15 Leu Val Leu Ala Phe Ser Ile Thr Tyr Thr Pro Ile Met Ile Tyr Ala 20 25 30 Leu Lys Val Ser Arg Gly Arg Leu Leu Gly Leu Leu His Ile Leu Ile 35 40 45 Phe Leu Asn Cys Ser Phe Thr Phe Gly Tyr Met Thr Tyr Val His Phe 50 55 60 Gln Ser Ala Asn Arg Val Ala Leu Thr Leu Gly Ala Val Val Ala Leu 65 70 75 80 Leu Trp Gly Val Tyr Ser Leu Thr Glu Ser Trp Lys Phe Ile Thr Ser 85 90 95 Arg Cys Arg Leu Cys Cys Leu Gly Arg Arg Tyr Ile Leu Ala Pro Ala 100 105 110 His His Val Glu Ser Ala Ala Gly Leu His Ser Ile Ser Ala Ser Gly 115 120 125 Asn Arg Ala Tyr Ala Val Arg Lys Pro Gly Leu Thr Ser Val Asn Gly 130 135 140 Thr Leu Val Pro Gly Leu Arg Ser Leu Val Leu Gly Gly Lys Arg Ala 145 150 155 160 Val Lys Arg Gly Val Val Asn Leu Val Lys Tyr Gly Arg 165 170 10 128 PRT Porcine reproductive and respiratory syndrome virus 10 Met Ala Gly Lys Asn Gln Ser Gln Lys Lys Lys Lys Ser Thr Ala Pro 1 5 10 15 Met Gly Asn Gly Gln Pro Val Asn Gln Leu Cys Gln Leu Leu Gly Ala 20 25 30 Met Ile Lys Ser Gln Arg Gln Gln Pro Arg Gly Gly Gln Ala Lys Lys 35 40 45 Lys Lys Pro Glu Lys Pro His Phe Pro Leu Ala Ala Glu Asp Asp Ile 50 55 60 Arg His His Leu Thr Gln Thr Glu Arg Ser Leu Cys Leu Gln Ser Ile 65 70 75 80 Gln Thr Ala Phe Asn Gln Gly Ala Gly Thr Ala Ser Leu Ser Ser Ser 85 90 95 Gly Lys Val Ser Phe Gln Val Glu Phe Met Leu Pro Val Gly His Thr 100 105 110 Val Arg Leu Ile Arg Val Thr Ser Thr Ser Ala Ser Gln Gly Ala Ser 115 120 125 11 840 DNA Porcine reproductive and respiratory syndrome virus 11 tctctagttt gtataaatta ctattagagg ttgttccgca aaaatgcggt gccacggaag 60 gggctttcat ctatgctgtt gagaggatgt tgaaggattg tccgagctcc aaacaggcca 120 tggcccttct ggcaaaaatt aaagttccat cctcaaaggc cccgtctgtg tccctggacg 180 agtgtttccc tacggatgtt ttagccgact tcgagccagc atctcaggaa aggccccaaa 240 gttccggcgc tgctgttgtc ctgtgttcac cggatgcaaa agagttcgag gaagcagccc 300 cggaagaagt tcaagagagt ggccacaagg ccgtccactc tgcactcctt gccgagggtc 360 ctaacaatga gcaggtacag gtggttgccg gtgagcaact gaagctcggc ggttgtggtt 420 tggcagtcgg gaatgctcat gaaggtgctc tggtctcagc tggtctaatt aacctggtag 480 gcgggaattt gtccccctca gaccccatga aagaaaacat gctcaatagc cgggaagacg 540 aaccactgga tttgtcccaa ccagcaccag cttccacaac gacccttgtg agagagcaaa 600 cacccgacaa cccaggttct gatgccggtg ccctccccgt caccgttcga gaatttgtcc 660 cgacggggcc tatactctgt catgttgagc actgcggcac ggagtcgggc gacagcagtt 720 cgcctttgga tctatctgat gcgcaaaccc tggaccagcc tttaaatcta tccctggccg 780 cttggccagt gagggccacc gcgtctgacc ctggctgggt ccacggtagg cgcgagcctg 840 12 22 DNA Artificial Sequence Description of Artificial Sequenceprimer 12 atcgggaatg ctcagtcccc tt 22 13 18 DNA Artificial Sequence Description of Artificial Sequenceprimer 13 gcgcataaga cagatcca 18 14 20 DNA Artificial Sequence Description of Artificial Sequenceprimer 14 aaggggactg agcattcccg 20 15 18 DNA Artificial Sequence Description of Artificial Sequenceprimer 15 cagaagggtt cgaggaag 18 16 21 DNA Artificial Sequence Description of Artificial Sequenceprimer 16 gcctgtccta acgccaagta c 21 17 21 DNA Artificial Sequence Description of Artificial Sequenceprimer 17 catgtccacc ctatcccaca t 21 18 42 DNA Artificial Sequence Description of Artificial Sequence oligonucleotide 18 agagcgggaa cagaatcctt cccaccttta gcggtacgct tg 42 19 16 DNA Artificial Sequence Description of Artificial Sequenceprimer 19 gcttggaact gcgagg 16 20 17 DNA Artificial Sequence Description of Artificial Sequenceprimer 20 tgaaggtgct ctggtct 17 21 15 DNA Artificial Sequence Description of Artificial Sequenceprimer 21 aaattcccgc ctacc 15 

What is claimed is:
 1. An isolated virus deposited under ATCC Accession Number PTA-2194.
 2. An isolated cell comprising a virus deposited under ATCC Accession Number PTA-2194.
 3. An isolated virus comprising an RNA polynucleotide comprising the RNA nucleotide sequence corresponding to SEQ ID NO:
 1. 4. An isolated polynucleotide comprising the sequence of SEQ ID NO:
 1. 5. An isolated polynucleotide wherein the sequence is SEQ ID NO:
 1. 6. An isolated polynucleotide having at least about 96% identity with a polynucleotide having the sequence shown in SEQ ID NO: 1 using a GAP algorithm with default parameters, wherein the polynucleotide replicates in a cell.
 7. A vector comprising a polynucleotide comprising the sequence shown in SEQ ID NO:
 1. 8. A polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NO:2-10.
 9. A polypeptide comprising an amino acid sequence having at least about 95% identity to SEQ ID NO:2.
 10. A polypeptide comprising an amino acid sequence having at least about 99% identity to SEQ ID NO:3.
 11. A polypeptide comprising an amino acid sequence having at least about 98% identity to SEQ ID NO:4.
 12. A polypeptide comprising an amino acid sequence having at least about 94% identity to SEQ ID NO:5.
 13. A polypeptide comprising an amino acid sequence having at least about 95% identity to SEQ ID NO:6.
 14. A polypeptide comprising an amino acid sequence having at least about 91% identity to SEQ ID NO:7.
 15. A polypeptide comprising an amino acid sequence having at least about 99% identity to SEQ ID NO:9.
 16. A polypeptide comprising an amino acid sequence having at least about 99.5% identity to SEQ ID NO:10.
 17. An antibody that specifically binds a European-like porcine reproductive and respiratory syndrome virus (PRRSV).
 18. A method of making an antibody, the method comprising administering to an animal a virus particle comprising an RNA polynucleotide comprising the RNA nucleotide sequence corresponding to SEQ ID NO:1 in an amount effective to cause the production of an antibody specific for the virus particle.
 19. The method of claim 18 wherein the antibody is selected from the group consisting of a polyclonal antibody and a monoclonal antibody.
 20. The method of claim 18 further comprising isolating the antibody.
 21. An antibody produced by the method of claim
 18. 22. A method of making an antibody, the method comprising administering to an animal a polypeptide comprising an amino acid sequence selected from the group consisting of SEQ ID NO:2-10, or a polynucleotide encoding the polypeptide, in an amount effective to cause the production of an antibody specific for the polypeptide.
 23. The method of claim 22 wherein the antibody is selected from the group consisting of a polyclonal antibody and a monoclonal antibody.
 24. The method of claim 22 further comprising isolating the antibody.
 25. An antibody produced by the method of claim
 22. 26. A method for detecting a PRRSV, the method comprising: contacting a virus particle with an antibody of claim 17, 21, or 22 under conditions to form a complex with a virus particle; and detecting the complex, wherein the presence of the complex indicates the presence of a PRRSV.
 27. The method of claim 26 wherein the virus particle is obtained from a biological sample.
 28. A method for detecting PRRSV in a porcine subject, comprising: providing a biological sample from a porcine subject; adding an antibody of claim 17, 21, or 22 to the sample under conditions to form a complex with a virus particle in the sample; and detecting the complex, wherein the presence of the complex indicates the presence of PRRSV.
 29. The method of claim 28 wherein the biological sample comprises lung tissue.
 30. A kit for use in detecting PRRSV in a porcine subject, the kit comprising the antibody of claim 17, 21, or 22 and instructions for using the antibody.
 31. A method for detecting the presence of a European-like PRRSV, comprising: contacting a viral polynucleotide with a first primer and a second primer under conditions suitable to form a detectable amplification product, wherein the first primer comprises a nucleotide sequence that is complementary to nucleotides 2268 and 2269 of SEQ ID NO: 1 or the complement thereof; and detecting an amplification product, wherein the detection indicates that the viral polynucleotide is a European-like PRRSV.
 32. The method of claim 31 wherein the first primer comprises a nucleotide sequence selected from the group consisting of 5′ATCGGGAATGCTCAGTCCCCTT (SEQ ID NO:12), and 5′-AAGGGGACTGAGCATTCCCG (SEQ ID NO:14).
 33. A method for detecting the presence of a European-like PRRSV in a porcine subject comprising: contacting a biological sample of a porcine subject with a first primer and a second primer and incubating under conditions suitable to form a detectable amplification product, wherein the first primer comprises a nucleotide sequence that is complementary to nucleotides 2268 and 2269 of SEQ ID NO: 1 or the complement thereof; and detecting an amplification product, wherein the detection indicates that the porcine subject has a European-like PRRSV.
 34. The method of claim 33 wherein the first primer comprises a nucleotide sequence selected from the group consisting of 5′ATCGGGAATGCTCAGTCCCCTT (SEQ ID NO:12), and 5′-AAGGGGACTGAGCATTCCCG (SEQ ID NO:14).
 35. The method of claim 33 wherein the biological sample comprises lung tissue.
 36. A kit for use in detecting PRRSV in a porcine subject, the kit comprising the first primer and a second primer of claim 31 or 33 suitable for use in amplification of a portion of a PRRSV and instructions for using the primer pair.
 37. A kit for use in detecting antibody to PRRSV in a porcine subject, the kit comprising the virus of claim 1 and instructions for using the virus.
 38. An immunogenic composition comprising an attenuated or inactivated PRRSV comprising a polynucleotide having at least about 96% identity with a polynucleotide having the sequence shown in SEQ ID NO: 1 using a GAP algorithm with default parameters.
 39. An immunogenic composition comprising a polypeptide selected from the group consisting of SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, an immunogenic analog thereof, an immunogenic fragment thereof, and a combination thereof.
 40. A method of treating a porcine subject at risk of infection with a PRRSV or displaying symptoms of a PRRSV infection, comprising administering to the animal an immunogenic composition comprising an attenuated or inactivated PRRSV comprising a polynucleotide having at least about 96% identity with comprising an RNA polynucleotide comprising the RNA nucleotide sequence corresponding to SEQ ID NO: 1 using a GAP algorithm with default parameters, wherein the immunogenic composition is administered in an amount effective to cause an immune response to the PRRSV.
 41. A method of treating a porcine subject at risk of infection with a PRRSV or displaying symptoms of a PRRSV infection, comprising administering to the animal an immunogenic composition comprising a polypeptide selected from the group consisting of SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, an immunogenic analog thereof, an immunogenic fragment thereof, and a combination thereof, wherein the immunogenic composition is administered in an amount effective to cause an immune response to the polypeptide.
 42. A method of treating a porcine subject at risk of infection with a PRRSV or displaying symptoms of a PRRSV infection, comprising administering to the animal a neutralizing antibody, wherein the neutralizing antibody is administered in an amount effective to treat the porcine subject.
 43. A kit for use in detecting antibody to PRRSV in a porcine subject, the kit comprising the virus of claim 3 and instructions for using the virus. 